2013 Fall Medium Range Discussion

[Srain]

Major battle between the seasonal base state and the robust MJO wave upcoming...

One of the things I've noticed is the pattern is somewhat similar to what we out West into the Southern Plains just experience over the past 3-4 weeks. While the MJO was less than cooperative during late December/early January, the indications of a noisy STJ do raise an eyebrow.

[am19psu]

What are your thoughts on that? I noticed it appeared it could be a moderate event.

Dynamical models side with the Walker Circulation. Statistical models keep the MJO trucking across the Western Hemisphere and into Africa and the IO through the next 20 days. Questions >> Answers...

[mahk_webstah]

The Euro Ensembles and GEFS as well as the CPC Super Ensembles are suggesting the Western Ridge breaks down and a cold and stormy regime becomes established once again across the West Coast/Great Basin and into the Plains.

 

01182013 00Z Euro Ensembles 00zECMWFENS500mbHeightAnomalyNA240.gif

01182013 06Z GEFS 06zgfsensembles500mbHeightAnomalyNA264.gif

01182013 CPC 500hgt_comp_sup814.gif

merely a reloading of the cold?  MJO more robust going into Phase 8 and beyond?  Strat Warming effect?  On balance, this would be brief and then the cold overwhelms again?

[Srain]

It appears we are going to get some G-IV Winter Recon across the Pacific for the upcoming pattern due to the uncertainty. There are also indications that a favorable MJO pulse will arrive during the late January time frame and suggests a noisy Sub Tropical Jet will return as well.

 

WEATHER RECONNAISSANCE FLIGHTS
CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.
1230 PM EST THU 17 JANUARY 2013
SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)
         VALID 18/1100Z TO 19/1100Z JANUARY 2013
         WSPOD NUMBER.....12-048

 

I.  ATLANTIC REQUIREMENTS
    1. NEGATIVE RECONNAISSANCE REQUIREMENTS.
    2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

 

II. PACIFIC REQUIREMENTS
    1. FLIGHT ONE --NOAA 49--
.      A. P56/ DROP 11(44.3N 151.0W)/ 19/0000Z
       B. NOAA9 02WSC TRACK56
       C. 18/1930Z
       D. 16 DROPS ON TRACK AS PUBLISHED
       E. AS HIGH AS POSSIBLE/ 19/0600Z

    2. SUCCEEDING DAY OUTLOOK.....NEGATIVE.

 

 

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1048 AM EST FRI JAN 18 2013

 

VALID 12Z MON JAN 21 2013 - 12Z FRI JAN 25 2013

 

...BITTER COLD ACROSS THE UPPER GREAT LAKES AND NORTHERN NEW
ENGLAND...
...ARCTIC CHILL DESCENDS UPON THE EASTERN UNITED STATES...

 

MEDIUM RANGE FLOW PATTERN EAST OF 100W WILL BE DOMINATED BY A
QUASI-STATIONARY UPPER-LEVEL TROUGH OVER HUDSON BAY/EASTERN
CANADA. BY THE DAY 5-6 TIME FRAME...THE PREVAILING UPPER-LEVEL
RIDGE IN THE WEST ERODES WITH A STRONG WAVE MIGRATING THROUGH THE
PACIFIC NORTHWEST...NORTHERN ROCKIES AND NORTHERN PLAINS. GOOD
CONTINUITY WAS MAINTAINED ALONG THE WEST COAST...USING A MANUAL
BLEND OF THE 18/00Z GUIDANCE...INCLUDING THE ECMWF MEANS AND
ASPECTS OF THE OPERATIONAL ECMWF/GFS MASS FIELD FORECASTS.

 

GFS/ECMWF OPERATIONALS WERE IN GOOD AGREEMENT TO DAY 4.5 (22/00Z)
WITH THE CORE OF THE ARCTIC AIRMASS SLOWLY MIGRATING
EAST-NORTHEASTWARD FROM THE UPPER MS VALLEY TO MAINE AND NORTHERN
NEW ENGLAND. THERE ARE FEW DIFFERENCES BETWEEN THESE 2 PIECES OF
GUIDANCE WITH THIS OVERALL AREAL SPREAD OF THIS MODIFIED ARCTIC
BOUNDARY THROUGH DAY 6 IN THE MIDWEST...EAST...SOUTHEAST...AND
WITH A GRADUAL WARMUP FROM WEST TO EAST ACROSS THE
NORTHERN/CENTRAL HIGH PLAINS. BY DAY 4...THERE IS REASONABLE
EVIDENCE OF A COASTAL WAVE DEVELOPING ATOP THIS SLOPED ARCTIC
FRONT...AND BENEATH A COMPLEX 250MB JET STRUCTURE EAST OF THE
MISSISSIPPI RIVER. ENOUGH SUPPORT/EVIDENCE DURING THE LAST 48
HOURS TO REQUEST A SERIES OF NOAA G4 WINTER RECON FLIGHTS TO
SAMPLE THE NORTH CENTRAL PACIFIC BETWEEN HAWAII AND ALASKA.

 

THE 18/00Z GFS WAS NOT A BAD PIECE OF GUIDANCE ON DAY 6 IN
MT/WY/ND/SD/WRN NE GENERALLY BECAUSE THE OPERATIONAL ECMWF WAS WAY
OVERDONE WITH LEE SIDE CYCLOGENESIS (AN ALBERTA CLIPPER)
DEVELOPING ALONG THE UPPER FRONT ASSOCIATED WITH PACIFIC FLOW
INVADING FROM THE WEST. THE ECMWF'S 990MB SURFACE LOW ON DAY 6-7
MIGRATING ACROSS ND/MN LOOKED OUT OF PLACE GIVEN THE LACK OF
LOW-LEVEL MOISTURE RETURN FROM THE WESTERN GOMEX...A PRONOUNCED
UPPER-LEVEL TROUGH AND DOWNSTREAM ARCTIC BOUNDARY ENTRENCHED
ACROSS THE GREAT LAKES AND EASTERN CONUS. MANUAL GRAPHICS
PREFERRED A MANUAL BLEND OF THE GFS/ECMWF MEAN AT THE SURFACE.
ALOFT...WOULD EXPECT SOME SORT OF MID-LEVEL CLIPPER-TYPE SYSTEM TO
EXIT THE SOUTHERN CANADIAN ROCKIES...BUT A STRENGTHENING SYSTEM
THE MAGNITUDE A SURFACE WAVE/CLIPPER SYSTEM NEAR 990 MB WOULD BE
AN EXTREME EXAMPLE OF MERGING POLAR/MARITIME JET STREAM
INTERACTIONS. A 'DEEP' CLIPPER WOULD TYPICALLY BOTTOM OUT IN THE
998 MB ISH RANGE AT BEST. I STARTED OUT THE DAY 6-7 GRAPHICS WITH
A 'WEAK' SYSTEM TRACKING THROUGH THE GREAT LAKES/MIDWEST.

 

THE SURFACE GRAPHICS DID PART WAYS WITH ASPECTS OF THE 18/00Z GFS
AND GEFS UPSTREAM...IN PARTICULAR...ACROSS THE EAST AND CENTRAL
PACIFIC AFTER DAY 5. THE 18/00Z GEFS/GFS ARE UNUSUALLY SLOW WITH
THE PROGRESSION OF A DEEP WAVE IN THE NORTHERN STREAM WESTERLIES
ALONG 45-50N LATITUDE. THIS IS THE TIME FRAME WE BROKE AWAY FROM
THE PREVIOUS GRAPHICS AND SIDED WITH THE ECMWF MEANS. THIS DOES
NOT CHANGE THE FRONTAL PROGRESSION AND COLD ADVECTION PATTERN
PROJECTED DAYS 5-7. IF ANYTHING...IT ALLOWS FOR SOME SHORTWAVE
RIDGING (AND MID-LEVEL WARM ADVECTION) TO DEVELOP DOWNSTREAM AND
LEE OF THE US ROCKIES PRIOR TO THE CLIPPER'S INTERACTION WITH THE
POLAR JET DOWNSTREAM OVER CENTRAL NORTH AMERICA AND THE NORTHERN
PLAINS.

 

VOJTESAK

[Amped]

It appears we are going to get some G-IV Winter Recon across the Pacific for the upcoming pattern due to the uncertainty. There are also indications that a favorable MJO pulse will arrive during the late January time frame and suggests a noisy Sub Tropical Jet will return as well.

WEATHER RECONNAISSANCE FLIGHTS

CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.

1230 PM EST THU 17 JANUARY 2013

SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)

VALID 18/1100Z TO 19/1100Z JANUARY 2013

WSPOD NUMBER.....12-048

I. ATLANTIC REQUIREMENTS

1. NEGATIVE RECONNAISSANCE REQUIREMENTS.

2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

II. PACIFIC REQUIREMENTS

1. FLIGHT ONE --NOAA 49--

. A. P56/ DROP 11(44.3N 151.0W)/ 19/0000Z

B. NOAA9 02WSC TRACK56

C. 18/1930Z

D. 16 DROPS ON TRACK AS PUBLISHEDPOp

E. AS HIGH AS POSSIBLE/ 19/0600Z

2. SUCCEEDING DAY OUTLOOK.....NEGATIVE.

EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD

1048 AM EST FRI JAN 18 2013

VALID 12Z MON JAN 21 2013 - 12Z FRI JAN 25 2013

...BITTER COLD ACROSS THE UPPER GREAT LAKES AND NORTHERN NEW

ENGLAND...

...ARCTIC CHILL DESCENDS UPON THE EASTERN UNITED STATES...

MEDIUM RANGE FLOW PATTERN EAST OF 100W WILL BE DOMINATED BY A

QUASI-STATIONARY UPPER-LEVEL TROUGH OVER HUDSON BAY/EASTERN

CANADA. BY THE DAY 5-6 TIME FRAME...THE PREVAILING UPPER-LEVEL

RIDGE IN THE WEST ERODES WITH A STRONG WAVE MIGRATING THROUGH THE

PACIFIC NORTHWEST...NORTHERN ROCKIES AND NORTHERN PLAINS. GOOD

CONTINUITY WAS MAINTAINED ALONG THE WEST COAST...USING A MANUAL

BLEND OF THE 18/00Z GUIDANCE...INCLUDING THE ECMWF MEANS AND

ASPECTS OF THE OPERATIONAL ECMWF/GFS MASS FIELD FORECASTS.

GFS/ECMWF OPERATIONALS WERE IN GOOD AGREEMENT TO DAY 4.5 (22/00Z)

WITH THE CORE OF THE ARCTIC AIRMASS SLOWLY MIGRATING

EAST-NORTHEASTWARD FROM THE UPPER MS VALLEY TO MAINE AND NORTHERN

NEW ENGLAND. THERE ARE FEW DIFFERENCES BETWEEN THESE 2 PIECES OF

GUIDANCE WITH THIS OVERALL AREAL SPREAD OF THIS MODIFIED ARCTIC

BOUNDARY THROUGH DAY 6 IN THE MIDWEST...EAST...SOUTHEAST...AND

WITH A GRADUAL WARMUP FROM WEST TO EAST ACROSS THE

NORTHERN/CENTRAL HIGH PLAINS. BY DAY 4...THERE IS REASONABLE

EVIDENCE OF A COASTAL WAVE DEVELOPING ATOP THIS SLOPED ARCTIC

FRONT...AND BENEATH A COMPLEX 250MB JET STRUCTURE EAST OF THE

MISSISSIPPI RIVER. ENOUGH SUPPORT/EVIDENCE DURING THE LAST 48

HOURS TO REQUEST A SERIES OF NOAA G4 WINTER RECON FLIGHTS TO

SAMPLE THE NORTH CENTRAL PACIFIC BETWEEN HAWAII AND ALASKA.

THE 18/00Z GFS WAS NOT A BAD PIECE OF GUIDANCE ON DAY 6 IN

MT/WY/ND/SD/WRN NE GENERALLY BECAUSE THE OPERATIONAL ECMWF WAS WAY

OVERDONE WITH LEE SIDE CYCLOGENESIS (AN ALBERTA CLIPPER)

DEVELOPING ALONG THE UPPER FRONT ASSOCIATED WITH PACIFIC FLOW

INVADING FROM THE WEST. THE ECMWF'S 990MB SURFACE LOW ON DAY 6-7

MIGRATING ACROSS ND/MN LOOKED OUT OF PLACE GIVEN THE LACK OF

LOW-LEVEL MOISTURE RETURN FROM THE WESTERN GOMEX...A PRONOUNCED

UPPER-LEVEL TROUGH AND DOWNSTREAM ARCTIC BOUNDARY ENTRENCHED

ACROSS THE GREAT LAKES AND EASTERN CONUS. MANUAL GRAPHICS

PREFERRED A MANUAL BLEND OF THE GFS/ECMWF MEAN AT THE SURFACE.

ALOFT...WOULD EXPECT SOME SORT OF MID-LEVEL CLIPPER-TYPE SYSTEM TO

EXIT THE SOUTHERN CANADIAN ROCKIES...BUT A STRENGTHENING SYSTEM

THE MAGNITUDE A SURFACE WAVE/CLIPPER SYSTEM NEAR 990 MB WOULD BE

AN EXTREME EXAMPLE OF MERGING POLAR/MARITIME JET STREAM

INTERACTIONS. A 'DEEP' CLIPPER WOULD TYPICALLY BOTTOM OUT IN THE

998 MB ISH RANGE AT BEST. I STARTED OUT THE DAY 6-7 GRAPHICS WITH

A 'WEAK' SYSTEM TRACKING THROUGH THE GREAT LAKES/MIDWEST.

THE SURFACE GRAPHICS DID PART WAYS WITH ASPECTS OF THE 18/00Z GFS

AND GEFS UPSTREAM...IN PARTICULAR...ACROSS THE EAST AND CENTRAL

PACIFIC AFTER DAY 5. THE 18/00Z GEFS/GFS ARE UNUSUALLY SLOW WITH

THE PROGRESSION OF A DEEP WAVE IN THE NORTHERN STREAM WESTERLIES

ALONG 45-50N LATITUDE. THIS IS THE TIME FRAME WE BROKE AWAY FROM

THE PREVIOUS GRAPHICS AND SIDED WITH THE ECMWF MEANS. THIS DOES

NOT CHANGE THE FRONTAL PROGRESSION AND COLD ADVECTION PATTERN

PROJECTED DAYS 5-7. IF ANYTHING...IT ALLOWS FOR SOME SHORTWAVE

RIDGING (AND MID-LEVEL WARM ADVECTION) TO DEVELOP DOWNSTREAM AND

LEE OF THE US ROCKIES PRIOR TO THE CLIPPER'S INTERACTION WITH THE

POLAR JET DOWNSTREAM OVER CENTRAL NORTH AMERICA AND THE NORTHERN

PLAINS.

VOJTESAK

Huh is this to use up the budget. Don't see any real threats on the models just cold and dry with maybe some lake effect stuff.

[am19psu]

Huh is this to use up the budget. Don't see any real threats on the models just cold and dry with maybe some lake effect stuff.

Compare GFS and Euro at D6.

[DaculaWeather]

 

000NOUS42 KNHC 181527REPRPDWEATHER RECONNAISSANCE FLIGHTSCARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.1025 AM EST FRI 18 JANUARY 2013SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)         VALID 19/1100Z TO 20/1100Z JANUARY 2013         WSPOD NUMBER.....12-049I.  ATLANTIC REQUIREMENTS    1. NEGATIVE RECONNAISSANCE REQUIREMENTS.    2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.II. PACIFIC REQUIREMENTS    1. NEGATIVE RECONNAISSANCE REQUIREMENTS.    2. SUCCEEDING DAY OUTLOOK.....NEGATIVE.    3. REMARKS: MISSION ON TRACK 56 FOR 19/0000Z       WILL FLY AS SCHEDULED ON WSPOD 12-048.$$JWP

 

EXTENDED FORECAST DISCUSSIONNWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD1048 AM EST FRI JAN 18 2013VALID 12Z MON JAN 21 2013 - 12Z FRI JAN 25 2013

 

...THERE IS REASONABLEEVIDENCE OF A COASTAL WAVE DEVELOPING ATOP THIS SLOPED ARCTICFRONT...AND BENEATH A COMPLEX 250MB JET STRUCTURE EAST OF THEMISSISSIPPI RIVER. ENOUGH SUPPORT/EVIDENCE DURING THE LAST 48HOURS TO REQUEST A SERIES OF NOAA G4 WINTER RECON FLIGHTS TOSAMPLE THE NORTH CENTRAL PACIFIC BETWEEN HAWAII AND ALASKA.

Any idea what this about?

[donsutherland1]

Some evening thoughts...

 

1. Consistent with Message #452 in this thread from 1/7, I believe we are now at the transition where much of the rest of January will likely see below normal readings in the eastern half to perhaps two-thirds of the nation.

 

2. During that remainder of the month, there will likely be transient trough in the west at some point, but it will probably come eastward.

 

3. Already, the lower Mid-Atlantic has received a moderate to locally significant snowfall. Another moderate to possibly significant snowfall could be a possibility in the Mid-Atlantic, New England, and/or Ohio Valley at some point before the month comes to an end. A possible timeframe might be the 1/24-1/27 period given some of the recent model runs and ensembles.

 

4. As we head toward February, one of the stronger analogs that has been coming up over the past week is 1967. Adding support for that emerging idea is the recent cooling of ENSO Region 3.4 and the latest CFSv2 monthly forecast. If this emerging idea is right, February could wind up the coldest month of the winter relative to normal across much of North America.

[QVectorman]

Hey fella just a quick up date got the revised GWO numbers in earlier today as HM and I have been eluding to lots of chaos in the atm this week especially and the up coming week so I take extra precaution with the GWO numbers to get the revised ones because they have been looking pretty squirrely and the revised are lagging by about 2 days and the GWO has forecast time of 14-23 days so being that some signals can only go out 14 and I'm already 2 days behind the GFS 16 days is already ahead of me LOL. Anyways, what's shaken out with the strat and GWO analogs for the last week of Jan and early Feb. As talked about the other day, the xt RTW that was in the pacific back on wednesday appears it will still be coming over the ridge while breaking the ridge down a bit and still on schedule to arrive late 24 early 25th east of the MS. Ushering cooler air for Jan 26-29 (matching Don's thoughts) and a reinforcement of colder air for Jan 31-Feb 2 (this one looks like a decent shot) and then a 5-10 degree warm up for Feb 2-4 with another S/W-shot of cold Feb 5-7 (decent shot of cold here to) and S/W cooler air Feb 7-11. There is a xt RW over India right now that I circled that times out to arriving Feb 4/5 which adds credence to the Feb. 5-7 time frame for a S/W moving through the East Coast. These dates were more time pertinent and I was too busy to post this, this morning. But I will post thoughts for beyond Feb. 11 on Monday when more ppl are back from the weekend. 

[blizzard1024]

The GFS ensembles have been insanely cold in the northeast/mid atlantic at days 10-16 run after run after run

for the past couple days at least ( I did not check earlier). see below.  

 

 

Usually by days 10-16 or sometimes sooner, all the anomalies get smeared out by model ensemble spread.

I have been watching these charts for years and can't recall such a persistent cold trough as I have

seen lately. It could just be the GFS ensembles going extreme but run after run after run??? is it onto

something for the first week of February??? 

[Srain]

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1058 AM EST SAT JAN 19 2013

VALID 12Z TUE JAN 22 2013 - 12Z SAT JAN 26 2013


ARCTIC AIRMASS REMAINS A FIXTURE IN THE EAST AND MIDWEST DURING
THE MEDIUM RANGE PERIOD. VERY LITTLE CHANGE FROM THE PREVIOUS
GRAPHICS CONCERNING THE SERIES OF ARCTIC BOUNDARIES EXPECTED TO
MIGRATE SOUTHEASTWARD OUT OF SOUTH CENTRAL CANADA AND SPREAD OUT
ACROSS THE GREAT LAKES...NORTHEAST AND SOUTHEAST.

THE IMPORTANT DETAIL IN THE GRAPHICS WILL BE EXACTLY WHERE THE
SUCCESSION OF ARCTIC BOUNDARIES SETTLE OUT AND MODIFY BETWEEN
35N-40N AND 85W-70W AS MID-LEVEL ENERGY TRACKS THROUGH THE BASE OF
THE COLD UPPER-LEVEL TROUGH. THE GENERAL TREND OVER THE LAST 2-3
DAYS HAS BEEN CONSISTENT WITH A FLATTER FLOW PATTERN AND LITTLE TO
NO AMPLIFICATION OF THE UPPER-LEVEL FLOW AS THESE DISTURBANCES
PASS ATOP THE SLOPED ARCTIC FRONT(S). IN OTHER
WORDS...'SUPPRESSED' DISTURBANCES WILL INTENSIFY INVOF THE COASTAL
CAROLINA AND RACE OUT TO THE EAST NORTHEAST...SOUTH/EAST OF THE
40N 70W BENCHMARK.

THE 06Z GEFS/OPERATIONAL GFS WERE GOOD PIECES OF GUIDANCE TO
INCORPORATE INTO THE BLEND THIS MORNING. IN PARTICULAR...THE
OPERATIONAL 06Z GFS IN THE WEST AND IN THE EAST...THE 00Z GEFS.
THE DIFFERENCE BETWEEN THE 00Z GEFS AND 06Z GEFS MEAN SOLUTION WAS
SUBTLE WITH TRACK/INTENSITY OF A  POSSIBLE COASTAL WAVE...DAYS 6-7
ALONG THE MID ATLANTIC COAST NORTHWARD INTO THE GULF OF MAINE.

IN THE CENTRAL SECTION OF THE NATION...THE TRAJECTORIES OF THE
INDIVIDUAL SURGES/FRONT WILL ALLOW FOR GREATER MODIFICATION OF THE
ARCTIC AIRMASS...AND CONSEQUENTLY...LARGER DIURNAL TEMPERATURE
SWINGS...IN THE CENTRAL AND SOUTHERN PLAINS PLAINS ARE IN THE
OFFING THIS FORECAST CYCLE.

A BREAKDOWN OF THE UPPER-LEVEL RIDGE IN THE WEST APPEARS TO BE ON
TRACK DAY 3-5. MANUAL GRAPHICS FAVORED A BLEND OF THE 00Z ECMWF
MEANS AND 06Z GEFS MEANS.

VOJTESAK

 

[DaculaWeather]

Another good discussion today, it's long, here's part of it. They are sending another recon flight out and have apparently gotten good data from it..

http://www.daculaweather.com/4_hpc_extended_disco.php

 

EXTENDED FORECAST DISCUSSION...CORRECTION ...LINES 23/24NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD1106 AM EST SUN JAN 20 2013VALID 12Z WED JAN 23 2013 - 12Z SUN JAN 27 2013

 

FORECAST CHALLENGES ARE MANY ALONG THE SOUTHERN FRINGES OF THEARCTIC BOUNDARY FROM THE SOUTH CENTRAL HIGH PLAINS...EASTWARDACROSS THE SOUTHEAST AND PIEDMONT. FROM P-TYPE AND MAX TEMPS TOUNSEASONABLY LOW MIN TEMPS IN THE DEEP SOUTH AND MODEL QPF OUTPUTALONG THE NORTHEAST COAST... THE RUN-TO-RUN VARIATION/SPREADREMAINS LARGE. AS IT RELATES TO THE CONSIDERABLE SPREAD...WHAT HAS BEEN ANINTERESTING ARTIFACT OF THE WINTER RECON OUTPUT IS HOW THEINFLUENCE OF PERTURBATIONS IN THE SOUTHERN STREAM OFF THECALIFORNIA COAST ACT TO SUPPRESS THE SURFACE WAVE TRACK ATOP THEARCTIC DRAPE ALONG 40N_LATITUDE AND EAST OF 95W_LONGITUDE.

[Srain]

Another good discussion today, it's long, here's part of it. They are sending another recon flight out and have apparently gotten good data from it..

http://www.daculaweather.com/4_hpc_extended_disco.php

 

EXTENDED FORECAST DISCUSSION...CORRECTION ...LINES 23/24NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD1106 AM EST SUN JAN 20 2013VALID 12Z WED JAN 23 2013 - 12Z SUN JAN 27 2013

 

FORECAST CHALLENGES ARE MANY ALONG THE SOUTHERN FRINGES OF THEARCTIC BOUNDARY FROM THE SOUTH CENTRAL HIGH PLAINS...EASTWARDACROSS THE SOUTHEAST AND PIEDMONT. FROM P-TYPE AND MAX TEMPS TOUNSEASONABLY LOW MIN TEMPS IN THE DEEP SOUTH AND MODEL QPF OUTPUTALONG THE NORTHEAST COAST... THE RUN-TO-RUN VARIATION/SPREADREMAINS LARGE. AS IT RELATES TO THE CONSIDERABLE SPREAD...WHAT HAS BEEN ANINTERESTING ARTIFACT OF THE WINTER RECON OUTPUT IS HOW THEINFLUENCE OF PERTURBATIONS IN THE SOUTHERN STREAM OFF THECALIFORNIA COAST ACT TO SUPPRESS THE SURFACE WAVE TRACK ATOP THEARCTIC DRAPE ALONG 40N_LATITUDE AND EAST OF 95W_LONGITUDE.

Steve, additional WSR has been tasked and hopefully that additional data will provide some clarity in medium range as there remains a great deal of volatility from run to run of the operational global guidance.

 

 

WEATHER RECONNAISSANCE FLIGHTS

CARCAH, NATIONAL HURRICANE CENTER, MIAMI, FL.

1055 AM EST SUN 20 JANUARY 2013

SUBJECT: WINTER STORM PLAN OF THE DAY (WSPOD)

         VALID 21/1100Z TO 22/1100Z JANUARY 2013

         WSPOD NUMBER.....12-051

I.  ATLANTIC REQUIREMENTS

    1. NEGATIVE RECONNAISSANCE REQUIREMENTS.

    2. OUTLOOK FOR SUCCEEDING DAY.....NEGATIVE.

II. PACIFIC REQUIREMENTS

    1. FLIGHT ONE -- NOAA 49

       A. P52/ DROP 10 (22.3N 129.0W)/ 22/0000Z

       B. NOAA9 04WSC TRACK52

       C. 21/1930Z

       D. 19 DROPS ON TRACK AS PUBLISHED.

       E. 41,000 TO 45,000 FT/ 22/0600Z

    2. OUTLOOK FOR SUCCEEDING DAY:

       A. P46/ DROP 7/ 23/0000Z

    3. REMARKS: TRACK P52 WITH A CONTROL TIME OF 21/0000Z

       WILL BE FLOWN AS SCHEDULED ON WSPOD 12-050.

$$

JWP

 

[cbmclean]

From the full discussion as found on the Dacula weather link given above, I found the following text.

 

"THE PREMISE HERE IS...AND THE FORECAST PHILOSOPHY FOR THE SYNOPTIC-SCALE FRONTS...ETC AND THE MEDIUM RANGE TEMPS/POPS..."

 

Huh?  Do you Mets understand that?  Do the ellipses represent where someone deleted text?  What exactly is the author trying to communicate?

[DaculaWeather]

Steve, what do you really think they are after here, at least as far as what the main concern might be?  I understand some type of winter storm, but maybe something more specific that might be triggering their interest?

[Srain]

Steve, what do you really think they are after here, at least as far as what the main concern might be?  I understand some type of winter storm, but maybe something more specific that might be triggering their interest?

The uncertainty is in the Day 6 and beyond time frame. The main concerns are the short waves crossing the Pacific and the interaction with the stalled Artic boundary. Also of concern is the Kelvin Wave as well as the increased activity should the MJO finally move into a 8/1 scenario. That would tend to favor a stormy pattern across the West/Great Basin and on ENE as a noisy STJ become established. What we'll need to watch is the January 28th, +/- a couple of day’s time frame. There are indications that a potent system will develop across the Southern Rockies/Southern Plains as the Western Ridge breaks down and the EPO/PNA regime become more favorable for Southern tracking storms as we enter the late January/early February time frame. That said there remain a great deal of uncertainty as to just exactly how the pattern will evolve and who/where will benefit from the upcoming pattern, IMO.

[thenewbigmack]

The uncertainty is in the Day 6 and beyond time frame. The main concerns are the short waves crossing the Pacific and the interaction with the stalled Artic boundary. Also of concern is the Kelvin Wave as well as the increased activity should the MJO finally move into a 8/1 scenario. That would tend to favor a stormy pattern across the West/Great Basin and on ENE as a noisy STJ become established. What we'll need to watch is the January 28th, +/- a couple of day’s time frame. There are indications that a potent system will develop across the Southern Rockies/Southern Plains as the Western Ridge breaks down and the EPO/PNA regime become more favorable for Southern tracking storms as we enter the late January/early February time frame. That said there remain a great deal of uncertainty as to just exactly how the pattern will evolve and who/where will benefit from the upcoming pattern, IMO.

Looking into analog years for the MJO, I'm not seeing a favorable pattern for the West at all. This is what I'm coming up with when the MJO was in phases 8/1 with a amp of 1.5 and greater...

 

[am19psu]

From the full discussion as found on the Dacula weather link given above, I found the following text.

 

"THE PREMISE HERE IS...AND THE FORECAST PHILOSOPHY FOR THE SYNOPTIC-SCALE FRONTS...ETC AND THE MEDIUM RANGE TEMPS/POPS..."

 

Huh?  Do you Mets understand that?  Do the ellipses represent where someone deleted text?  What exactly is the author trying to communicate?

ellipses equal commas

[DaculaWeather]

http://www.daculaweather.com/4_hpc_extended_disco.php

 

I'm liking the sound of this more and more...a few excerpts: 

 

EXTENDED FORECAST DISCUSSIONNWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD407 AM EST MON JAN 21 2013VALID 12Z THU JAN 24 2013 - 12Z MON JAN 28 2013

 

GIVEN THE COLD ANTECEDENT CONDITIONS...THISSYSTEM WILL LIKELY RESULT IN CONSIDERABLE ICE/SNOW AMOUNTS ALONGAND NEAR THE TRACK OF THE LOW.

 

...UPDATE...ALL PARAMETERS FOR DAYS 3 AND 4 WERE UPDATED TO REFLECT A 00ZUKMET/00Z GEFS MEAN COMPROMISE...WHICH IS MUCH SLOWER AND SOUTHWARD WITH THE LOW TRACK FROM THESOUTHERN PLAINS TOWARD THE OHIO VALLEY.

[DaculaWeather]

Looks like the trend is warmer

 

[WidreMann]

ellipses equal commas

Or dashes in this case.

[Srain]

Major Winter Storm Late January thoughts:

All eyes turn W as the upper Ridge that has brought plentiful sunshine and a January thaw to our region breaks downs down and a deep trough and potent upper air disturbances moves onshore in California and drops SSE. At the base of that Western trough, a powerful storm system develops and attempts to close off. Further N along the British Colombia/Pacific NW Coast another potent storm system moves inland setting the stage for embedded short wave activity sliding S along the W flank of the deepening trough to our W. Moisture flowing off the Gulf returns in earnest at all levels in response to the Western trough and deepening storm across Arizona/Northern Mexico as pressures fall. The Euro and its ensembles are slower and deeper with this developing storm along with the Canadian and the GEFS. The operational GFS is a bit more progressive and a tad less stormy, but there are strong indications that the Euro idea is the more likely solution and additional Winter Storm RECON is tasked for the overnight hours tonight.

Beginning Monday into Tuesday, cold air building across Western Canada is pulled S into the Great Basin while warm air with increasing Gulf moisture streams N into the Southern Plains. As we saw with the Christmas Storm, such a scenario tends to suggest winter weather in the Cold sector and a severe threat in the Warm sector. The eventual track of the upper closed cold core low will be key as to where the wintry mischief falls and exactly where the greatest threat for severe weather may unfold. Another fly in the ointment is the MJO and a noisy sub tropical jet. This is a very complex and complicated weather pattern, but the trends suggest a potent Winter Storm is ahead for next week with potential wide spread societal impacts from the West Coast into the Southern Rockies/Southern Plains on N and E into the Ohio/Tennessee Valley Regions.

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[donsutherland1]

At 11 pm, tempertures included 20° in Washington, DC, 16° in Philadelphia, 14° in New York City, and 15° in Boston. Winter's coldest period, likely to stretch 3-4 weeks from this point into the middle or perhaps latter part of February has probably gotten underway.

 

Based on ENSO (neutral to borderline La Niña conditions for February and the teleconnections into early February/weight given to some of the past years for teleconnections similar to those of this winter), the most persistent teleconnection analog for February is 1967. The second one is 1963. A distant third was 1962. Those analogs suggest that the eastern half of the U.S. and southern Canada could be colder than normal for February.

 

My latest teleconnection analogs for February 2013 result in the following temperature anomalies:

 

All three of those years saw some frigid readings in that area during the first half of February. 1963 saw the cold last through much of the month. Needless to say, the baseline temperature normals (1981-2010 vs. 1951-80) have warmed. Nonetheless, even taking that into consideration it is likely that the coldest reading could be near 0° in Boston (a subzero low cannot be ruled out), between 7° and 12° in New York City and Philadelphia, and probably between 12°-17° in Washington, DC by the worst of the cold ends by mid-February.

 

Nationwide, February 1967 was the 48th coldest February on record. However, in the Northeast it ranked 17th, Ohio Valley 27th, and Southeast 25th. While I don't believe readings will approach the levels of 1967 given the contemporary baseline norms, the important point is that the Ohio Valley, Northeast (New England/Mid-Atlantic), and Southeast could be colder and perhaps much colder than today's norms.

 

In terms of snowfall, February will probably prove to be the snowiest month of the winter. Snowfall in the Middle Atlantic and New England regions and possibly Ohio Valley could be above normal.

 

1967 featured a KU snowstorm during the February 5-8 timeframe. During the onset of the snowstorm, the GWO was in Phase 4, the AO was neutral and the PNA was positive (a PNA and AO scenario that is plausible going into the first week in February according to the GFS ensembles). In terms of February KU snowstorms, Phase 4 was actually an uncommon one. Phase 8 was the most common (37%). Phases 6-8 accounted for 63% of February KU snowstorms. Phases 1-5 accounted for just 37% of KU snowstorms. Recently, the GWO was in Phase 5.

 

On account of the KU snowstorm, the Mid-Atlantic and New England areas were much snowier than normal in 1967. In contrast, 1963 saw much less snowfall, but that year featured an exceptionally cold February (among the 10 coldest in the Northeast and Southeast). 1962 saw above normal snowfall in the Mid-Atlantic region and much above normal snowfall in New England.

[Srain]

Unsettled/Colder Pattern Returns To Much Of North American:

The pleasant pattern we have enjoyed across the West and Plains will be winding down as an unsettled takes hold by the weekend and lingers to the end of January.

A weak frontal boundary will slowly meander S on Thursday and pull up stationary some where across Central/E Texas into Southern Louisiana by Friday. Moisture will begin to slowly increase as a return flow off the Gulf with increasing dew point take hold and foggy nights with cloudy warmer days become the theme as we head into the weekend. A series of short waves across the Plains may bring a chance of isolated storms and rain chances Saturday into Sunday across the Eastern half of Texas into Louisiana.

To our W, a developing trough will break down the upper ridge that has been present for a week to 10 days and a series of upper air disturbances dig S into California and the Baja Region of Western Mexico. Meanwhile additional energy further N across W and Southern Canada along the Polar Jet will deepen and a positive tilted trough will develop from the Great Lakes SW to NW Mexico. Pressure falls to our W will increase a southerly onshore flow from the Gulf bringing increased moisture with PW's nearing the 1.7 to 2.0 range which is very high for the time of year. To our W across N Arizona and New Mexico snow will develop as moisture and colder air from Western Canada filters S into the Great Basin and into the Rockies. A series of upper air disturbances with embedded short waves will drop S into Southern California and round the base of the trough and ripple ENE.

By early next week, a strong storm system will develop to our W and begins a slow march across Northern Mexico into New Mexico and the Southern Plains. The SPC has outlined a Day 7 Risk for Arkansas, but has noted that the Risk area will likely be reconfigured as better continuity becomes available in future model guidance and the eventual evolution of the pattern developing becomes clearer. At this time a stronger cold front looks likely in the mid next week time frame. The fly in the ointment continues to be a strong MJO (octant/phase 8) and a noisy sub tropical jet pattern that may well lead to over running moisture over a shallow cool air mass as we end January and begin February.

 

 

DAY 4-8 CONVECTIVE OUTLOOK 
   NWS STORM PREDICTION CENTER NORMAN OK
   0348 AM CST WED JAN 23 2013
  
   VALID 261200Z - 311200Z
  
   ...DISCUSSION...
   A PATTERN SHIFT APPEARS LIKELY NEXT WEEK...WITH A SEVERE WEATHER
   THREAT DEVELOPING OVER PORTIONS OF THE SRN PLAINS AND LOWER MS
   VALLEY.
  
   ON SAT/D4...THE ERN TROUGH WILL MOVE OFFSHORE...ALLOWING FOR A
   TEMPORARILY ZONAL FLOW REGIME ACROSS MUCH OF THE CONUS. MODELS DO
   INDICATE A LOWER LATITUDE SHORTWAVE TROUGH MOVING INTO THE SRN HIGH
   PLAINS LATE SAT INTO SUN/D5...AND THIS SYSTEM WILL LIKELY INTERACT
   WITH A MOISTENING AIR MASS TO THE S TO PRODUCE THUNDERSTORMS OVER
   TX...OK...AND KS. WEAK INSTABILITY SHOULD PRECLUDE ANY SEVERE THREAT
   WITH THIS SYSTEM.
  
   AS THIS TROUGH CONTINUES EWD ACROSS THE MID MS AND OH VALLEYS...IT
   WILL LOSE AMPLITUDE WHILE A LARGER TROUGH TAKES SHAPE ACROSS THE WRN
   STATES. THE PASSAGE OF THE LEAD TROUGH WILL ENHANCE THE SEVERE
   POTENTIAL ASSOCIATED WITH THE NEXT TROUGH BY PRIMING THE AIR MASS
   WITH MID 60S F BOUNDARY LAYER DEWPOINTS ON MON/D6...A FULL DAY IN
   ADVANCE OF THE LARGER TROUGH.
  
   TIMING DIFFERENCES DO EXIST BETWEEN VARIOUS MODEL SOLUTIONS AND
   ENSEMBLE MEMBERS. STILL...THE LIKELY PRESENCE OF SUBSTANTIAL WARM
   SECTOR MOISTURE...AS WELL AS A BROAD AREA OF STRONG DEEP LAYER SHEAR
   AND FORCING ALL SUGGEST SEVERE WEATHER IS PROBABLE. THE MAIN
   UNCERTAINTY IS WHERE THE THREAT WILL INITIATE...MATURE...AND
   DIMINISH. GIVEN MODEL AGREEMENT OF THE LARGE SCALE PATTERN IN A
   CLIMATOLOGICALLY FAVORABLE AREA...WILL INTRODUCE SEVERE FOR TUE/D7
   CENTERED OVER AR.
  
   THIS SEVERE AREA IS LIKELY TO CHANGE SHAPE AND SHIFT IN SUBSEQUENT
   OUTLOOKS AS MODEL GUIDANCE CHANGES.
  
   ..JEWELL.. 01/23/2013
 

[Srain]

HPC Morning Medium Range Update:

 

EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
1047 AM EST WED JAN 23 2013

 

VALID 12Z SAT JAN 26 2013 - 12Z WED JAN 30 2013

 

IN PRINCIPLE GUIDANCE MAINTAINS GOOD AGREEMENT IN SHOWING THAT A
TROF NEARING THE WEST COAST AS OF DAY 3 SAT WILL AMPLIFY AS IT
PROGRESSES INTO THE WRN-CNTRL CONUS WHILE A RIDGE BUILDS OVER THE
ERN PACIFIC.  TELECONNECTIONS RELATIVE TO THE UPSTREAM RIDGE THAT
BECOMES ESTABLISHED OVER THE ERN PAC SUPPORT THE IDEA THAT SOME
ENERGY WITHIN THIS TROF MAY BE PULLED SWWD OVER AND BEYOND THE
SWRN CONUS/EXTREME NWRN MEXICO.  THIS FEATURE WILL BRING A BROAD
AREA OF MSTR AND BELOW NORMAL DAYTIME TEMPS TO THE WEST AND
ULTIMATELY LEAD TO A SIGNIFICANT WARMING TREND AHEAD OF IT.  BY
THE MIDDLE OF NEXT WEEK AFOREMENTIONED TELECONNECTIONS INDICATE
BEST CHANCES FOR PCPN SHOULD BE CENTERED OVER THE TN VLY/SOUTHEAST
WITH A DRIER TREND OVER THE WEST.

 

WHILE ENSEMBLE MEANS HAVE HELD ONTO A FAIRLY STABLE EVOLUTION OVER
THE CONUS AND VICINITY DURING THE PAST DAY OR SO... OPERATIONAL
MODELS CONTINUE TO DIFFER FROM RUN TO RUN AND AMONG EACH OTHER
WITH RESPECT TO THE DISTRIBUTION OF ENERGY WITHIN THE MODERATELY
PROGRESSIVE AND POSITIVELY TILTED MEAN TROF.  THE 00Z GFS IS MORE
AMPLIFIED THAN CONSENSUS WITH ENERGY ON THE WRN SIDE OF THE ERN
PAC TROF DAY 3 SAT AND BY DAYS 6-7 TUE-WED BECOMES FAST WITH THE
SRN HALF OF THE MEAN TROF AXIS.  THE 06Z GFS ADJUSTED TO A MUCH
SLOWER/CLOSED LOW SOLN WHICH AT LEAST FALLS MORE WITHIN THE
CONSENSUS ENSEMBLE MEAN TROF AXIS... THOUGH THE 06Z GFS IS ON THE
DEEPER EDGE OF THE ENVELOPE.  THE PAST TWO OPERATIONAL ECMWF RUNS
LIE BETWEEN THE 00Z AND 06Z GFS EXTREMES AND BY LATE IN THE PERIOD
MAY HAVE LESS SWWD ELONGATION OF ENERGY THAN RECOMMENDED BY
TELECONNECTIONS.

 

IN LEADING NRN STREAM FLOW GFS RUNS IN PARTICULAR HAVE BEEN
ERRATIC AND NOT WELL SUPPORTED BY MOST OTHER SOLNS FOR SHRTWV
DETAILS... FAVORING A CONSENSUS APPROACH.  SOME SPREAD IS ALSO
NOTED WITH TIMING OF THE SHRTWV EJECTING NEWD FROM THE SWRN
CONUS/NWRN MEXICO SAT ONWARD.  THE GFS... ESPECIALLY THE 06Z
RUN... TRENDS FAST ONCE THE FEATURE REACHES THE PLAINS WHILE THE
00Z ECMWF IS A BIT ON THE SLOWER SIDE OF THE SPREAD.  THIS SHRTWV
WILL BE RESPONSIBLE FOR AN AREA OF PCPN SPREADING NEWD FROM THE
SRN ROCKIES WITH SOME SNOW PSBL IN THE NRN PART OF THE MSTR SHIELD.

 

THE RELATIVE CONSISTENCY OF THE ENSEMBLE MEANS... PLUS A SUBTLE
TREND OF GEFS MEANS TOWARD THE ECMWF MEANS THAT HAVE HAD A LITTLE
MORE SWWD ELONGATION OF THE MEAN TROF AND FURTHER TREND OF THE 06Z
GEFS MEAN IN THAT RESPECT RELATIVE TO THE 00Z RUN... YIELD A
PREFERENCE FOR A 70/30 BLEND OF THE 00Z ECMWF MEAN/06Z GEFS MEAN
AS THE STARTING POINT FOR THE DAYS 3-7 FCST.  RELATIVE TO
CONTINUITY LATEST CONSENSUS IS SLOWER WITH THE FRONT REACHING THE
GULF COAST AS OF EARLY DAY 3 SAT.  BY DAY 7 WED THERE IS A
SLIGHTLY FASTER TREND WITH THE NRN HALF OF THE FRONT REACHING THE
EAST.  AT THE VERY LEAST THE UNCERTAINTY IN RELATIVE INFLUENCE OF
THE AMPLIFIED PATTERN VERSUS UPSTREAM FLOW SEPARATION ALLOWING FOR
FASTER NRN STREAM PROGRESSION FAVORS TIMING SLOWER THAN THE 00Z
CMC AND ITS ENSEMBLE MEAN BUT FASTER THAN THE 00Z ECMWF.

RAUSCH

[thunderbolt]

 Don a quick question you mentioned the ao pna but not the nao was the nao neg or pos those years? as always keep up the great work.  chris

[uncle W]

At 11 pm, tempertures included 20° in Washington, DC, 16° in Philadelphia, 14° in New York City, and 15° in Boston. Winter's coldest period, likely to stretch 3-4 weeks from this point into the middle or perhaps latter part of February has probably gotten underway.

 

Based on ENSO (neutral to borderline La Niña conditions for February and the teleconnections into early February/weight given to some of the past years for teleconnections similar to those of this winter), the most persistent teleconnection analog for February is 1967. The second one is 1963. A distant third was 1962. Those analogs suggest that the eastern half of the U.S. and southern Canada could be colder than normal for February.

 

My latest teleconnection analogs for February 2013 result in the following temperature anomalies:

 

All three of those years saw some frigid readings in that area during the first half of February. 1963 saw the cold last through much of the month. Needless to say, the baseline temperature normals (1981-2010 vs. 1951-80) have warmed. Nonetheless, even taking that into consideration it is likely that the coldest reading could be near 0° in Boston (a subzero low cannot be ruled out), between 7° and 12° in New York City and Philadelphia, and probably between 12°-17° in Washington, DC by the worst of the cold ends by mid-February.

 

Nationwide, February 1967 was the 48th coldest February on record. However, in the Northeast it ranked 17th, Ohio Valley 27th, and Southeast 25th. While I don't believe readings will approach the levels of 1967 given the contemporary baseline norms, the important point is that the Ohio Valley, Northeast (New England/Mid-Atlantic), and Southeast could be colder and perhaps much colder than today's norms.

 

In terms of snowfall, February will probably prove to be the snowiest month of the winter. Snowfall in the Middle Atlantic and New England regions and possibly Ohio Valley could be above normal.

 

1967 featured a KU snowstorm during the February 5-8 timeframe. During the onset of the snowstorm, the GWO was in Phase 4, the AO was neutral and the PNA was positive (a PNA and AO scenario that is plausible going into the first week in February according to the GFS ensembles). In terms of February KU snowstorms, Phase 4 was actually an uncommon one. Phase 8 was the most common (37%). Phases 6-8 accounted for 63% of February KU snowstorms. Phases 1-5 accounted for just 37% of KU snowstorms. Recently, the GWO was in Phase 5.

 

On account of the KU snowstorm, the Mid-Atlantic and New England areas were much snowier than normal in 1967. In contrast, 1963 saw much less snowfall, but that year featured an exceptionally cold February (among the 10 coldest in the Northeast and Southeast). 1962 saw above normal snowfall in the Mid-Atlantic region and much above normal snowfall in New England.

February 1962 had frequent snowfalls but no heavy ones...The minimum was four on the 11th...

February had three snowfalls an inch or more...The first one was about two inches on the 2nd with a little more the following night...Friday February 9th had a wet snow event that was 2.9"...The first snowfall I ever put a ruler in...I measures 2" of slush on the sidewalk in front of my house...It got very cold after that with a minimum of 4 on the 11th...On the 14th the city got a snow to rain event but all snow to the north...the city picked 2.6" while over 7" fell to the north...March saw some super blocking that added to the Ash Wed. storm...

February 1963 was colder than 1962 but with less precipitation and snowfall...The first half of February featured quick arctic shots with flurries...The minimum was minus 2 on the 8th...A cold rain on the 11-12th...February 19th had a wet snow and rain event...2.5" of very wet snow...Near 10" well north...more cold and a few light snow events to close out the month...

February 1967 was very cold and snowy in the NYC area...On the second the temperature hit 58 degrees for a record high...That evening after a cold front passed it was snowing...The 6-7th had two snowfalls...One minor and one major...A blizzard on the 7th...A minimum of 6 on the 8th and 4 on the 13th...A quick thaw and back to frequent snowfalls...One of the best February's I ever lived thru...February 1967 and February 1962 had frequent snow events...1964 also...February 1967 was the only month to produce a KU storm...

[donsutherland1]

 Don a quick question you mentioned the ao pna but not the nao was the nao neg or pos those years? as always keep up the great work.  chris

 

Thunderbolt,

 

The February NAO figures for the 3 years I cited were as follows:

 

1962: +0.55

1963: -0.96

1967: +0.19

[donsutherland1]

February 1962 had frequent snowfalls but no heavy ones...The minimum was four on the 11th...

February had three snowfalls an inch or more...The first one was about two inches on the 2nd with a little more the following night...Friday February 9th had a wet snow event that was 2.9"...The first snowfall I ever put a ruler in...I measures 2" of slush on the sidewalk in front of my house...It got very cold after that with a minimum of 4 on the 11th...On the 14th the city got a snow to rain event but all snow to the north...the city picked 2.6" while over 7" fell to the north...March saw some super blocking that added to the Ash Wed. storm...

February 1963 was colder than 1962 but with less precipitation and snowfall...The first half of February featured quick arctic shots with flurries...The minimum was minus 2 on the 8th...A cold rain on the 11-12th...February 19th had a wet snow and rain event...2.5" of very wet snow...Near 10" well north...more cold and a few light snow events to close out the month...

February 1967 was very cold and snowy in the NYC area...On the second the temperature hit 58 degrees for a record high...That evening after a cold front passed it was snowing...The 6-7th had two snowfalls...One minor and one major...A blizzard on the 7th...A minimum of 6 on the 8th and 4 on the 13th...A quick thaw and back to frequent snowfalls...One of the best February's I ever lived thru...February 1967 and February 1962 had frequent snow events...1964 also...February 1967 was the only month to produce a KU storm...

 

Uncle W,

 

It will be interesting to see if the short warmup shown on the GFS is followed by snow that coincides with a return to colder weather. That might offer some hints as to whether the 1967 idea will play out. Hopefully, we'll get some decent snowfall.

[Srain]

Late January Winter Storm Morning thoughts:

 

Fog continues to plague much of our region (Texas/Oklahoma/Louisiana) as temps and dew points continue to rise daily. A very slow moving weak frontal boundary is draped across the Red River Valley and will slowly drop a bit further S before stalling and washing out over the weekend.

 

Attention then turns to our W. A Gulf of Alaska storm will begin to move inland along the Pacific NW and drop S into Southern California during the late weekend time frame. Very rich Pacific tropical moisture will stream inland across the W and into the Great Basin/Desert SW setting the stage for a very wet and stormy pattern in California, Arizona and New Mexico. As the storm system drops into Southern California, cold air from NW Canada will drop S into the Great Basin where temps will fall to the 10-20 degree below normal range. Valley rains and higher elevation wet snow will develop this weekend to our W. Across the Central Plains/Mid West and Great Lake, wintry weather can be expected as short wave energy approaches from the SW with light totals expected as the Arctic boundary retreats.

 

Across Texas, Oklahoma and Louisiana, deep Gulf moisture will surge inland as pressures fall to our W setting the stage for a warm, breezy and humid Monday into Tuesday of next week. There are differences that are still being seen via the guidance as they flip flop and switch scenario solutions. The 00Z Euro and its ensembles swapped place with the GFS/GEFS suggesting a more progressive positive tilted trough sweeping across Texas on Tuesday/Wednesday, while the GFS/GEFS is now slower. The GGEM is even slower to eject the energy off of Baja along the NW Coast of Mexico and is suggesting a 500mb low will linger most of next week. PW's rise to nearly 2 standard deviations above normal for this time of year for the NW Gulf Coast which raises an eyebrow for a heavy rainfall potential if capping can be overcome due to a SW flow aloft ahead of the approaching storm/trough to the W.

 

The SPC has outlined a Day 6 issuance that includes NE TX/SE OK/N LA/AR/SE MO/S IL/W KY/E TN. As the SPC discussion explains, this outline area may need to be reconfigured during the next several days due to the lack of continuity via the Global operational and ensemble guidance.

 

In the cold sector, snow levels are expected to drop to the desert valley floor early next week into the mid week time frame as much colder air filters S. Wintry weather will also be an issue N of the Arctic boundary as cyclogenesis begins Monday/Tuesday across the Southern Plains as the 500mb trough axis begins to eject E and very cold air builds across the Northern Plains/Great Lakes Region. Very heavy rainfall is possible along the Northern Gulf Regions into the SE as training storms are possible. This remains a very complex and complicated forecast, so expect changes as we head into the weekend and early next week.

 

HPC QPF:

 

SPC Day 6:

 

Euro Ensemble Mean:

 

GEFS:

 

GGEM: