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January 22-23 Mid Atlantic Storm Thread #3 - No Banter

stormtracker

By stormtracker,
in Mid Atlantic

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Ravens94

Ravens94

Posted
Posted

One thing is clear 12z models other then the NAM is changing the entire look of the precip shield 00z had a nice defined area 12z its blochy and messy http://www.stormvistawxmodels.com/img/cmc/current/12z/CMC_MSLPThickQPF_ma_f75.png

988 East of VA eastern shore http://www.stormvistawxmodels.com/img/cmc/current/12z/CMC_MSLPThickQPF_ma_f78.png
 

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chris87

chris87

Posted
Posted

I don't think it is a very good run...Last night's run made more sense....

 

 

i think to everyone's point -- the overall evolution largely remains the same but there is a good deal of run-to-run variability in the shape/distribution of vorticity lobes within the larger closer 5H low which seem to play a bit of a role in the sfc/qpf evolution (for better or worse) and much like exact location of banding is beyond the limits of predictability at these time scales

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PhineasC

PhineasC

Posted
Posted

One thing is clear 12z models other then the NAM is changing the entire look of the precip shield 00z had a nice defined area 12z its blochy and messy http://www.stormvistawxmodels.com/img/cmc/current/12z/CMC_MSLPThickQPF_ma_f75.png

988 East of VA eastern shore http://www.stormvistawxmodels.com/img/cmc/current/12z/CMC_MSLPThickQPF_ma_f78.png

 

This storm is no longer about a big slug of front-running snows. We are now depending on the low to bomb out and park a deform band over us. Much riskier.

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ICEauctions

ICEauctions

Posted
Posted

Regarding the use of the Blizzard Watch product by Sterling. They do not have it listed in their Watch/Warning/Advisory definition page at http://www.weather.gov/lwx/WarningsDefined, which I think speaks to the rarity of its use in the LWX CWA. The significant point here being the confidence they have in the potential for these conditions outside of 12-18 hours in advance. 

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DCAlexandria

DCAlexandria

Posted
Posted

This storm is no longer about a big slug of front-running snows. We are now depending on the low to bomb out and park a deform band over us. Much riskier.

let's see what the euro says. It very well may keep the front end slug.

Sent from my iPhone using Tapatalk

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Deck Pic

Deck Pic

Posted
Posted

This storm is no longer about a big slug of front-running snows. We are now depending on the low to bomb out and park a deform band over us. Much riskier.

 

People are placing too much stock into a short range model that has no skill and a model that is getting kudos for being consistent, but isn't handling energy transfer and QPF distribution correctly......Not sure why you are overreacting to these 2 runs...

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Ltrain

Ltrain

Posted
Posted

This storm is no longer about a big slug of front-running snows. We are now depending on the low to bomb out and park a deform band over us. Much riskier.

I dont know. It still looked like the GFS had damn good precip over me for awhile on the front end. Back end scares me more.

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AlaskaETC

AlaskaETC

Posted
Posted

It's not a question that can be answered....Does it verify higher? I don't think so....Does it have the idea right with this storm? I think yes....You're not getting a foot while I get 3'

I don't think it's prudent to erase the possibility of 3 feet in or near DC. Climo goes out th window in a storm like this

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Ravens94

Ravens94

Posted
Posted

This storm is no longer about a big slug of front-running snows. We are now depending on the low to bomb out and park a deform band over us. Much riskier.

I don't Buy a NON front end slug. Lots of energy coming in from the south TONS of RH and lift and we all have Been here before the Front end should be fine Not like the 12z Models so far are trying to do (Other than NAM). overall past 8 runs of the GFS has basically been waffling around run to run to run. 12z euro had its off run yesterday May very well be hitting the GEM-GFS today. QPF is very blochy and its probably some feedback and transfer issues. Track is still good and hopefully tonight models can start getting precip right we all know its the worst part of a model. Everything aloft looks great. Mesoscale models will have a blast with this.

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ThePhotoGuy

ThePhotoGuy

Posted
Posted

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1059 AM EST WED JAN 20 2016

VALID 12Z SAT JAN 23 2016 - 12Z WED JAN 27 2016

THERE CONTINUES TO BE HIGH CONFIDENCE THAT A MAJOR EAST COAST
STORM WILL OCCUR BETWEEN THE SHORT RANGE AND MEDIUM RANGE
PERIODS...STARTING THURSDAY AND ENDING SUNDAY. THERE HAVE
BEEN...HOWEVER...SOME TRENDS OVER THE PAST COUPLE DAYS THAT APPEAR
TO AFFECT THE FORECAST FOR THE START OF THE MEDIUM RANGE FORECAST.


LOOKING AT THE TRENDS OF THE SURFACE LOW TRACKS/QPF
DISTRIBUTION...THERE HAS BEEN A SOUTHWARD/SLOWER TREND OF BOTH
OVER THE PAST 48 HOURS. THIS HAS IMPLICATIONS FOR WHERE THE
NORTHERN BOUNDARY OF THE SNOWFALL OCCURS...WITH A VERY SHARP
GRADIENT BETWEEN VERY HEAVY AND VERY LITTLE SNOW POSSIBLE. RIGHT
NOW...THIS AREA LIES OVER SOUTHERN AND CENTRAL NEW YORK AND NEW
ENGLAND. FARTHER SOUTH...THE HEAVIER SNOWFALL TOTALS HAVE ALSO
SHIFTED SOMEWHAT SOUTHWARD OVER THE PAST COUPLE DAYS AS WELL AS
THE ISSUE OF MIXING/CHANGEOVER. THE STATE OF VIRGINIA LIES WITHIN
THIS ZONE. FOR NOW. WHAT THE TRENDS WILL BE OVER THE NEXT COUPLE
DAYS WILL SORT OUT THE DETAILS.

WITH INDIVIDUAL OPERATIONAL MODEL RUNS...AS OPPOSED TO THE SUITE
OF ENSEMBLES...THERE ARE TRENDS THAT HAVE OCCURRED WITH RESPECT TO
WHAT WAS OCCURRING WITHIN THE LARGER ENSEMBLE SYSTEM. FOR
EXAMPLE...THE OPERATIONAL GFS OVER THE PAST 48 HOURS HAS REMAINED
LARGELY CONSISTENT...WHILE THE OVERALL TREND HAS BEEN SOUTH/SLOW.
THE ECMWF HAS VACILLATED SOUTH/NORTH WHILE THE UKMET HAS BEEN
FARTHER SOUTH AND THE CANADIAN HAS ALSO COME SOUTH BUT REMAINS ON
THE NORTHERN SIDE OF THE SOLUTIONS. THESE ARE ALL SOLUTIONS THAT
HAVE OCCURRED IN THE 3 TO 4 DAY FORECAST RANGE.

THERE IS ALSO ANOTHER IMPORTANT CONSIDERATION IN HOW QUICKLY THE
STORM EVOLVES AND EXITS ON DAYS 3 AND 4. BOTH THE 06Z GFS AND 00Z
ECMWF HAVE THE MAIN SURFACE LOW FARTHER WEST THAN THE MEANS SHOW
ON SUNDAY MORNING/DAY 4. THIS DIFFERENCE HAS AN IMPORTANT
POSSIBLE EFFECT ON IMPACT IF THE CURRENT OPERATIONAL RUNS ARE ON
THE SLOWER END OF THE SOLUTIONS. THE SPEED OF THE SYSTEM AFFECTS
HOW LONG THE SNOWFALL CONTINUES VERSUS A FASTER ENDING TIME. IN
GENERAL...THIS PARTICULAR SYSTEM IS A RELATIVE SLOW MOVER IN THAT
SNOWFALL COULD LAST AS LONG AS 36 HOURS AS OPPOSED TO PERHAPS MORE
TYPICAL JANUARY SYSTEMS THAT LAST FROM 12 TO 18 OR PERHAPS 24
HOURS.

SO...DESPITE THE GENERAL AGREEMENT BETWEEN A COMPLEX SUITE OF MANY
MODELS/ENSEMBLES...THERE ARE SOME SUBTLE BUT IMPORTANT DIFFERENCES
THAT CCOULD HAVE LARGE IMPACTS ON THE MOST POPULOUS AREA OF THE
COUNTRY.

GENERAL OVERVIEW...

THE EAST COAST SYSTEM WILL OCCUR THRU SATURDAY INTO SUNDAY...DAYS
3/SATURDAY AND 4/SUNDAY OF THE MEDIUM RANGE FORECAST. THIS SYSTEM
WILL BE GONE FOLLOWING DAY 4/SUNDAY FOLLOWED BY A SIGNIFICANT RISE
IN HEIGHTS IMPLYING A WARMUP ONCE THE SURFACE HIGH MOVES OFF THE
SOUTHEAST COAST ON DAYS 5 AND 6/MONDAY AND TUESDAY.

A SIGNIFICANT UPPER TROUGH WILL MOVE ACROSS THE CENTRAL WEST COAST
ON DAY 3/SATURDAY AND WILL PROGRESS EASTWARD ACROSS THE GREAT
BASIN/ROCKIES ON SUNDAY/DAY 4 TO THE MISSISSIPPI VALLEY ON
MONDAY/DAY 5. THIS SYSTEM WILL BE ASSOCIATED WITH A COLD FRONT
WITH MOSTLY MARITIME AIR IN ITS WAKE CROSS THE SOUTHWEST US AND
REACH THE SOUTHERN PLAINS ON DAY 5/MONDAY. LOW PRESSURE IS
EXPECTED TO DEVELOP IN THE MID MISSISSIPPI VALLEY AND CROSS THE
GREAT LAKES BY DAY 6/TUESDAY. THE ASSOCIATED COLD FRONT WILL MOVE
EAST TO THE EAST COAST ON DAY 6/TUESDAY AND WILL CONTINUE EASTWARD
OFFSHORE TO THE GULF COAST BY WEDNESDAY/DAY 7.

MODEL CHOICES AND CONFIDENCE...

THERE IS GENERAL AGREEMENT BETWEEN THE ENSEMBLE MEANS THROUGH DAY
7. IN PARTICULAR...
THE LATEST VERSIONS OF THE 06Z GFS AND THE 00Z ECMWF WITH THEIR
SUBTLE BUT IMPACTFUL DIFFERENCES AS DISCUSSED EARLIER...AS WELL AS
THE GEFS/ECMWF ENSEMBLE MEANS WERE REASONABLY SIMILAR ACROSS MUCH
OF THE NATION THROUGH DAY 6. THE OPERATIONAL RUNS START TO
DIVERGE ON DAY 7 BUT THEY ARE NOT UNREASONABLE WHEN COMPARED TO
THE MEANS. THEREFORE...THE FORECAST MAPS WERE NOT DIFFICULT TO
COMPOSE WITH A 60/40 BLEND OF OPERATIONAL/MEANS FOR DAYS 3 THROUGH
6 AND THE REVERSE FOR DAY 7.

KOCIN

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Deck Pic

Deck Pic

Posted
Posted

i think to everyone's point -- the overall evolution largely remains the same but there is a good deal of run-to-run variability in the shape/distribution of vorticity lobes within the larger closer 5H low which seem to play a bit of a role in the sfc/qpf evolution (for better or worse) and much like exact location of banding is beyond the limits of predictability at these time scales

 

It's not just the granular details and banding structure which we know a global won't get nailed down, but the GFS is acting much more Miller B'ish in terms of energy transfer and punching a dry slot into areas that will probably get nailed.  People are concerned that this front end will shut off and we will have to rely on deform...I don't agree...

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SNO

SNO

Posted
Posted

It's not a question that can be answered....Does it verify higher?  I don't think so....Does it have the idea right with this storm?  I think yes....You're not getting a foot while I get 3'

Thanks...makes more sense...the Shenandoah Valley typically does very well out here with events like this.

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RodneyS

RodneyS

Posted
Posted

Lol at Accuweather/USAToday still having Baltimore in the 6-12" range. Just lol. CZLI7YmWIAAfd3y.jpg

Weather Underground currently has a graphic for DC that shows 8-12 inches of snow on Friday and 12+ on Saturday.  However, if you click on each day individually, for Friday the text reads "snowfall around one inch" and for Saturday reads "snow accumulating 5 to 8 inches;"  see http://www.wundergro...:22222.3.99999?

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chris87

chris87

Posted
Posted

It's not just the granular details and banding structure which we know a global won't get nailed down, but the GFS is acting much more Miller B'ish in terms of energy transfer and punching a dry slot into areas that will probably get nailed.  People are concerned that this front end will shut off and we will have to rely on deform...I don't agree...

 

i'd agree with you -- i wouldn't be concerned either -- anyways i think everyone does well in the deformation once you smooth out the details

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bigjohndc

bigjohndc

Posted
Posted

Weather Underground currently has a graphic for DC that shows 8-12 inches of snow on Friday and 12+ on Saturday.  However, if you click on each day individually, for Friday the text reads "snowfall around one inch" and for Saturday reads "snow accumulating 5 to 8 inches;"  see http://www.wundergro...:22222.3.99999?

 

I would not trust this, but it breaks the individual days into two parts Friday/Friday night, and same for Saturday. It totals like 19 to 26 inches. 

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josh

josh

Posted
Posted

Weather Underground currently has a graphic for DC that shows 8-12 inches of snow on Friday and 12+ on Saturday.  However, if you click on each day individually, for Friday the text reads "snowfall around one inch" and for Saturday reads "snow accumulating 5 to 8 inches;"  see http://www.wundergro...:22222.3.99999?

Fri Night says 8-12", Sat day and night each separately say 5-8"

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Interstate

Interstate

Posted
Posted

Weather Underground currently has a graphic for DC that shows 8-12 inches of snow on Friday and 12+ on Saturday.  However, if you click on each day individually, for Friday the text reads "snowfall around one inch" and for Saturday reads "snow accumulating 5 to 8 inches;"  see http://www.wundergro...:22222.3.99999?

 

Models not Forecasts

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psuhoffman

psuhoffman

Posted
Posted

It bothers me a little that the storm seems to be changing from a front-end thump with a back side bomb to a wound up single low requiring tricky placement of a deform band. Outside that band most folks will get like a foot or so according to the GFS. The big totals are becoming more restricted on these runs.

I agree...WAA front end thumps like we got in 1996 and 2003 are money in the bank.  Not a lot of risk that goes wrong.  But as the models have shifted towards less of a primary low up west of the apps into Tenn and a quicker secondary taking over along the coast down towards the SC/GA coast versus eastern NC, that shuts off the WAA spike much sooner.  Once that happens we rely on the ccb and deform with the coastal, a much more complicated thing for the models to nail down.  Thats why we have started to see more shifting around with the qpf maxes run to run the last day or two then we did before that.  I am NOT being a downer at all, right now the coastal track and where it gets captured is perfect for our area to get a historic storm anyways, but it does raise the bust potential on truly epic totals verifying. 

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