Feb. 18-20, 2012 Disco/Analysis

[jburns]

I thought it was pretty much a done deal on anything wintry in the CAE area, but now I'm not sure sure anymore. GA might not even be out of the chance totally with current trends if they continue.

Speaking not from knowledge but from experience there will probably be a slight northward component in the final runs. It almost like the models are slow to overcome the inertia of an ongoing trend and have to pull things back a bit right at the end. I've seen it over and over again.

[SBUWX23]

It is the WRF, just at bit lower resolution and some tweaks in the model physics.

Yea, i think the NAM is catching up to the wrf. I'm not sure why they don't just go ahead and replace the NAM with it.

[HKY_WX]

It is the WRF, just at bit lower resolution and some tweaks in the model physics.

I'm not into the model physics, but I thought the WRF-NMM was eventually replacing the current NAM version on the NCEP site?

[WeatherNC]

Close to a 160kt 250mb jet core coming through with this vort, jburns is likely in the ballpark with respect to convective potential, expect at least a couple reports of thunder Sunday night.

18z

12z for comparison

[SBUWX23]

Im pretty sure the new NAM NEMS-B is a new version of the WRF-NMM but I could be wrong.

I'm not into the model physics, but I thought the WRF-NMM was eventually replacing the current NAM version on the NCEP site?

[jburns]

, jburns is likely in the ballpark with respect to convective potential,

OMG! I was correct in a weather post.

[griteater]

With respest to the deformation band, I believe that a good location to be in is right under the track of the closed off 700mb low.....is that correct?

Here's what I'm seeing with the 700mb low tracks:

18z NAM: Tupelo - Boone - Norfolk

12z WRF NMM: Tupelo - Asheville - Nags Head

[Vol Man]

Don't understand it at all. 18z NAM is brutal.

.SHORT TERM (TONIGHT THROUGH MONDAY)...CURRENT SURFACE ANALYSIS

SHOWS A WEAK COLD FRONT EXTENDING ACROSS THE OHIO RIVER VALLEY...

WITH A DEVELOPING LOW PRESSURE SYSTEM ALONG THE UPPER TEXAS COAST.

SATELLITE IMAGERY REVEALS AN EXTENSIVE AREA OF CLOUDS AND LIGHT RAIN

OVER THE DEEP SOUTH MOVING NORTHEASTWARD TOWARDS THE FORECAST AREA

AHEAD OF THIS LOW PRESSURE SYSTEM. IT APPEARS THAT THE CONVECTIVE

ACTIVITY ALONG THE NORTHERN GULF COAST WILL CUT-OFF A SIGNIFICANT

AMOUNT OF GULF MOISTURE FEEDING INTO OUR AREA. THUS...WHILE POPS

WILL BE HIGH TONIGHT FOR MEASURABLE RAINFALL...QPF AMOUNTS SHOULD BE

FAIRLY LIGHT UNTIL LATER TONIGHT TOWARDS SUNRISE AS THIS LOW MOVES

ACROSS CENTRAL ALABAMA. MODELS ARE IN GOOD AGREEMENT WITH PRODUCING

STRONG LIFT OVER THE CUMBERLAND PLATEAU AND CUMBERLAND MOUNTAINS ON

SUNDAY...AS UPPER-LEVEL DIVERGENCE INCREASES IN THE RIGHT ENTRANCE

REGION OF A STRONG UPPER-LEVEL JET AND FRONTOGENETICAL FORCING

STRENGTHENS OVER THE CUMBERLAND RANGE. WHILE IT APPEARS THAT THE

VERTICAL TEMP PROFILE WILL BE COLD ENOUGH FOR SNOW OVER SOUTHWEST VA

(ESPECIALLY ACROSS THE HIGHER ELEVATIONS)...THE NAM AND GFS MODELS

REVEAL SOME SIGNIFICANT DISCREPANCIES WITH THE VERTICAL TEMP PROFILE

OVER THE REST OF THE FORECAST AREA. IN FACT...THE NAM MODEL PROFILE

IS QUITE A BIT WARMER...ESPECIALLY AT THE 800 MB LAYER...WHICH WOULD

RESULT IN THE POSSIBILITY OF SLEET BEFORE CHANGING OVER TO SNOW.

WITH MODERATE TO OCCASIONALLY HIGH PRECIP RATES EXPECTED OVER THE

CUMBERLAND PLATEAU...THINK THAT SOME DYNAMICALLY COOLING COULD CAUSE

THE RAIN TO CHANGE TO SNOW QUICKER THAN THE MODELS WOULD CURRENTLY

SUGGEST. THIS QUICKER CHANGE OVER COULD RESULT IN WARNING-LEVEL

SNOWFALL AMOUNTS OVER THE NORTHERN CUMBERLAND PLATEAU. SINCE THIS

SCENARIO IS STILL UNCERTAIN...WILL CONTINUE WITH THE WINTER STORM

WATCH FOR THE PLATEAU...BUT WILL UPGRADE TO A WARNING ACROSS

SOUTHWEST VA AND NORTHEAST TN MOUNTAINS AND START IT EARLIER (AT

12Z). IN THE VALLEYS...WARM GROUND TEMPS FROM THE RECENT WARM

WEATHER SHOULD COMBINE WITH AFTERNOON SURFACE TEMPS LINGERING IN THE

UPPER 30S TO LOWER 40S TO CREATE A HOSTILE ENVIRONMENT FOR ANY

SNOWFALL ACCUMULATIONS UNTIL SUNDAY EVENING AS THE MOISTURE EXITS

THE REGION. THUS...THINK THAT ANY SNOWFALL ACCUMULATIONS IN THE

GREAT TN VALLEY SHOULD BE LIGHT BELOW 2500 FEET MSL. AS FOR THE

HIGHER ELEVATIONS...WILL GENERALLY CONTINUE WITH THE PREVIOUS

FORECAST`S SNOWFALL AMOUNTS. AS FOR TEMPS...NAM AND GFS GUIDANCE

NUMBERS ARE IN GOOD AGREEMENT THROUGH MONDAY...AND LOOK REASONABLE.

I understand being conservative, and I don't have to take the heat should things go wrong. But they need to educate the public w/ at least a special weather statement. The latest NAM slams NE TN, as does the Euro. Two great models to add support for potential significan accumulations - not a given but a real possibility. But I must say, that warm nose is pain and should be respected. But still, folks need to know the potential. I'm not sure what to think of that map - a warning to nothing in one county.

Carver...yes, they are usually more conservative, but after reading the forum all day, was still surprised they didn't have us at least in the 1-3 range.?!?

[Carvers Gap]

Carver...yes, they are usually more conservative, but after reading the forum all day, was still surprised they didn't have us at least in the 1-3 range.?!?

It is a peculiar map and I wonder if they don't have someone new working the evening shift. The zones don't look very coordinated. It's highly unusual to see a WSW end abruptly w/ no Special Weather Statement in the next county. My biggest concern is that there is potential for a significant winter storm, even if it does not pan out...and the public has not been warned. I guess there is not as big a rush since there is no rush hour tomorrow. The map doesn't necessarily look conservative, but odd. You can't just draw a straight line for a WSW and nothing happen just below the line. I know that geography is a problem, but that map will not verify.

[Cold Rain]

I'm almost hesitant to type a response to this, but honestly my thoughts are that if it closes off it could be a 6-8" snowfall under the deformation band anywhere it sets up, similar in intensity to the video eyewall posted back a few pages from 3/3/2010.

Never hesitate to respond with 6-8 inches! But thanks for the comment. I'd like to see some of the other incoming guidance start to move in the direction of the NAM. It seems like in a lot of these cases, the NAM tends to be a bit overdone on it's QPF maps, but that's just clinical observation more than anything else.

[Vol Man]

It is a peculiar map and I wonder if they don't have someone new working the evening shift. The zones don't look very coordinated. It's highly unusual to see a WSW end abruptly w/ no Special Weather Statement in the next county. My biggest concern is that there is potential for a significant winter storm, even if it does not pan out...and the public has not been warned. I guess there is not as big a rush since there is no rush hour tomorrow. The map doesn't necessarily look conservative, but odd.

I know...they usually would at least issue a SWS....I just noticed an updated map on Accuweather, and they still have us firmly in the 3-6 range??

[BIG FROSTY]

Blacksburg is still no go for Sig accumulations N.Foothills....

NCZ003-004-019-020-192115-

SURRY-STOKES-WILKES-YADKIN-

407 PM EST SAT FEB 18 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL NORTH CAROLINA

AND NORTHWEST NORTH CAROLINA.

.DAY ONE...TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

RAIN ON SUNDAY WILL CHANGE TO WET SNOW BY SUNDAY NIGHT WITH LIGHT

ACCUMULATIONS POSSIBLE...ESPECIALLY AT HIGHER ELEVATIONS

[Tacoma]

still can't believe that all nc mtns will not get in on the snow sunday afternoon.

[triadwx]

All of the Weather Services are being extremely conservative. It's nothing to fret about. They are looking at the same model data we are.

Blacksburg is still no go for Sig accumulations N.Foothills....

NCZ003-004-019-020-192115-

SURRY-STOKES-WILKES-YADKIN-

407 PM EST SAT FEB 18 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL NORTH CAROLINA

AND NORTHWEST NORTH CAROLINA.

.DAY ONE...TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

RAIN ON SUNDAY WILL CHANGE TO WET SNOW BY SUNDAY NIGHT WITH LIGHT

ACCUMULATIONS POSSIBLE...ESPECIALLY AT HIGHER ELEVATIONS

[chapelhillwx]

Here's RAH's disco... WWAs likely for all locations north of Hwy 64.

.SHORT TERM /SUNDAY AFTERNOON THROUGH SUNDAY NIGHT/...

AS OF 330 PM SATURDAY...

...A PERIOD OF WINTER WEATHER IS EXPECTED ACROSS PORTIONS OF CENTRAL

NORTH CAROLINA SUNDAY EVENING INTO SUNDAY NIGHT...

OVERVIEW:

THE LATEST GUIDANCE APPEARS TO HAVE A BETTER HANDLE ON THE EVOLUTION

OF THE UPPER LEVEL LOW (CURRENTLY IN THE CENTRAL PLAINS) AND THE

SOUTHERN STREAM WAVE (CURRENTLY IN TX) AS THEY APPROACH AND CROSS

THE AREA SUNDAY EVENING/NIGHT...THOUGH UNCERTAINTY IN THE SPECIFICS

(I.E. PTYPES/ACCUMULATION) PERSISTS. THE 12Z GFS/NAM/ECMWF INDICATE

THAT THE UPPER LEVEL LOW WILL TRACK SOUTHEAST FROM THE CENTRAL

PLAINS INTO KY AS AN OPEN WAVE BY 00Z MONDAY...THEN THROUGH CENTRAL

NC FROM WEST-EAST BETWEEN 03-09Z MONDAY. ALL MODELS INDICATE THAT

THE SFC LOW ASSOC/W THE ADVANCING SOUTHERN STREAM WAVE WILL REMAIN

ENTIRELY SOUTH OF CENTRAL NC...TRACKING FROM CENTRAL GA NORTHEAST

ALONG/OFFSHORE THE SC/NC COAST LATE SUNDAY AFTERNOON INTO SUNDAY

NIGHT. THE 12Z GFS/NAM/ECMWF ARE GENERALLY ON THE SAME PAGE AS THE

ECMWF HAS BEEN THE PAST FEW RUNS...SHOWING A DEEPER SFC LOW CLOSER

TO THE COAST FOR A PERIOD SUNDAY NIGHT.

MODEL DISCUSSION/CONFIDENCE:

THE 12Z MODEL GUIDANCE HAS COME INTO PRETTY CLOSE AGREEMENT AND

OVERALL CONFIDENCE IN THE FORECAST HAS INCREASED FOR SUNDAY

EVENING/NIGHT. ALL MODELS SHOW THE UPPER WAVE CURRENTLY IN THE

CENTRAL PLAINS TRACKING OVER CENTRAL NC ON THE HEELS OF THE SOUTHERN

STREAM WAVE BETWEEN 03-09Z SUNDAY...ALMOST IMMEDIATELY AFTER THE H85

LOW (EXPECTED TO TRACK EAST ALONG THE HIGHWAY 64 CORRIDOR SUNDAY

AFT/EVE) PUSHES OFFSHORE AND STRONG NORTHERLY LOW-LEVEL COLD

ADVECTION BEGINS ERODING THE H85 WARM-NOSE FROM N-S/NNW-SSE. THE

GFS/NAM/ECMWF ALL INDICATE ROUGHLY 0.20-0.25" OF LIQUID EQUIV PRECIP

BETWEEN 00-09Z MONDAY.

PRECIPITATION CHANCES:

WITH THE MODEL DISCUSSION IN MIND...WILL INDICATE CATEGORICAL PRECIP

CHANCES SUNDAY EVENING INTO SUNDAY NIGHT AS STRONG MID/UPPER LEVEL

ASCENT ASSOC/W THE SECONDARY SHORTWAVE PROGRESSES THROUGH THE AREA

IN THE PRESENCE OF A SATURATED OR NEAR SATURATED LOW-LEVEL AIRMASS.

EXPECT PRECIP CHANCES TO END FROM WEST-EAST BETWEEN 06-12Z MONDAY

MORNING IN ASSOC/W SYNOPTIC SUBSIDENCE/DRYING IN THE WAKE OF THE

AFOREMENTIONED SHORTWAVE.

WINTER WEATHER:

COMPLICATED PTYPE/ACCUMULATION FORECAST. THE SYNOPTIC REGIME IS

CLOSER TO A MILLER TYPE `A` SETUP...WHICH SUGGESTS THERE WILL BE A

NARROW RAIN/SNOW TRANSITION LINE WHICH WILL PROGRESS S/SE THROUGH

THE ENTIRE AREA ONCE THE H85 TRACKS EAST OF THE AREA BETWEEN 00-03Z

AND STRONG LOW-LEVEL COLD ADVECTION BEGINS. DESPITE GOOD OVERALL

AGREEMENT AMONG THE MODELS...SOME UNCERTAINTY PERSISTS W/REGARD TO

THE EXACT EVOLUTION OF THE UPPER LEVEL WAVE(S) AND THE SUBSEQUENT

TIMING/TRACK OF THE SURFACE/H85 LOW. SMALL CHANGES IN THE TIMING OR

TRACK OF THESE FEATURES COULD HAVE LARGE IMPLICATIONS ON THE TIMING

OF THE RAIN->SNOW CHANGEOVER AND THE POTENTIAL FOR SNOW ACCUMULATION

IN CENTRAL NC. THE LATEST MODEL GUIDANCE SUGGESTS THAT THE MOST

FAVORABLE LOCATION FOR ACCUMULATING SNOW WILL BE NORTH OF THE TRACK

OF THE H85 LOW WHERE MESOSCALE BANDING WOULD BE MORE LIKELY. THIS

EQUATES TO NEAR AND NORTH OF THE NC/VA BORDER BETWEEN 00-09Z OR

03-09Z MONDAY. SO...ALONG AND NORTH OF I-85 WILL HAVE THE BEST

POTENTIAL TO SEE 1" (PERHAPS 1-2") OF SNOW ACCUMULATION. ALTHOUGH

ANTECEDENT GROUND CONDITIONS ARE VERY WARM...GIVEN THAT IT WILL BE

NIGHT AND THAT STRONG COLD ADVECTION WILL BE PRESENT...FEEL THAT

ACCUMULATIONS WILL STILL BE POSSIBLE AS LONG AS PRECIPITATION IS

MODERATE AND PERSISTENT (2-4 HRS) IN THE PRESENCE OF THERMAL

PROFILES SUPPORTIVE OF SNOW. FROM HWY 64 TO THE I-85 CORRIDOR

(INCLUDING RALEIGH)...A CHANGEOVER FROM RAIN TO SNOW APPEARS LIKELY

BUT THE ACCUMULATION POTENTIAL IS MORE IN DOUBT SINCE IT WILL TAKE

LONGER FOR THE H85 WARM NOSE TO ERODE. SOUTH OF HWY 64...IT WILL

TAKE EVEN LONGER FOR THE H85 WARM-NOSE TO ERODE AND FCST SOUNDINGS

ALSO SHOW DRIER MID-LEVELS...WHICH WOULD SUGGEST LIGHT RAIN/DRIZZLE

CHANGING TO FREEZING RAIN/DRIZZLE INSTEAD OF SNOW...ASSUMING SFC

TEMPS CAN WETBULB BELOW FREEZING PRIOR TO PRECIPITATION ENDING. AT

THIS TIME...EXPECT THE BEST CHANCE FOR WINTER STORM WARNING CRITERIA

TO BE IN CENTRAL/SOUTHERN VA...AND A WINTER STORM WATCH WILL NOT BE

ISSUED. FEEL THAT A WINTER WEATHER ADVISORY WILL MOST LIKELY BE

NEEDED FOR ALL LOCATIONS NORTH OF HIGHWAY 64 SUNDAY EVENING INTO

SUNDAY NIGHT. HAVING SAID THAT...THE BEST CHANCE FOR MESOSCALE

BANDING AND ACCUMULATING SNOW IS ONLY 50-100 MILES NORTH IN

SOUTHERN/CENTRAL VA...AND A 50 MILE DIFFERENCE IN THE TRACK OF H85

LOW COULD BRING THE THREAT FOR ACCUMULATING SNOW FURTHER SOUTH INTO

CENTRAL NC...AND A POTENTIAL FOR WARNING CRITERIA TO BE MET NORTH OF

THE I-85 CORRIDOR.

ADDITIONALLY...WITH LOWS EXPECTED TO FALL BELOW FREEZING (UPPER 20S

TO LOWER 30S) IN MOST LOCATIONS PRIOR TO SUNRISE MONDAY MORNING...

BLACK ICE OR SLICK ROADWAYS WILL BE POSSIBLE LATE SUNDAY NIGHT

THROUGH SUNRISE MONDAY. -VINCENT

[SBUWX23]

not yet, they said most likely

Here's RAH's disco... WWAs for all locations north of Hwy 64.

[tnweathernut]

A question for the mets. The NAM clown map for northeast Tennessee is picked apart by MRX in regards to significant snowfall shown for upper east TN. MRX is stating that the warm nose at 800 will cause problems for accumulations. A piece of their discussion is below:

"...THE NAM MODEL PROFILE

IS QUITE A BIT WARMER...ESPECIALLY AT THE 800 MB LAYER...WHICH WOULD

RESULT IN THE POSSIBILITY OF SLEET BEFORE CHANGING OVER TO SNOW

Does the model not take into account the temps at ALL levels when showing the snowfall maps......or is MRX being ultra conservative?

[beanskip]

18z RGEM takes a pretty signficant south shift compared to 6z run. 6z at 36 had surface low over Chattanooga. 18z run has it south of ATL. 18z run also amps up the precip, even though surface low is 2mb weaker.

[beanskip]

RGEM at 36 then colder than 6z at 48. 850 line makes it almost to CAE -- it never really got below N.C/SC line on 6z run.

[BIG FROSTY]

All of the Weather Services are being extremely conservative. It's nothing to fret about. They are looking at the same model data we are.

I would have bet money there would have been at least a WWA with the afternoon package? That office is always the last to issue updates and everything... They will change the forecast 10 times before Monday. lol

[Brick Tamland]

All of the Weather Services are being extremely conservative. It's nothing to fret about. They are looking at the same model data we are.

I guess so. The models keep trending south with more and more snow, even at RDU, but RAH still doesn't seem ready to pull the trigger yet, The totals they are talking about seem to be a lot lower than the latest model runs show and what others on here, even mets, have said.

[BrierCreekWx]

Here is some information on the most recent NAM upgrade:

NCEP will introduce the use of the new NOAA Environmental Modeling System (NEMS), which is based on the tenets put forth by the Earth System Modeling Framework to which NOAA has subscribed. Eventually all of NCEP’s major modeling will be performed within NEMS. This NAM upgrade represents the first implementation of NEMS and a major step in the evolution of NCEP’s modeling suite.

The prediction model used in the NAM run will go from being the strictly regional Nonhydrostatic Mesoscale Model (NMM) to a new extended capability version now known as Nonhydrostatic Multiscale Model on B-grid (NMMB), which can be run either regionally or globally, and with or without embedded nests. This NEMS-NMMB will also serve as the prediction model running in the NAM Data Assimilation System (NDAS). Some of the model changes/ enhancements in the NEMS-NMMB include:

- Native horizontal grid is an Arakawa staggered B-grid (rotated 45 deg from the Arakawa E-grid in the WRF-NMM NAM)

- Modified vertical level distribution with more layers in the stratosphere (14 layers above 200 mb instead of 7 in the current operational NAM)

- Microphysics changes to produce higher peak reflectivities above 45 dBZ with higher peak surface rainfall rates in the high-resolution nests and more realistic grid-scale cloud fractions from cold, high cirrus.

- Change from USGS to MODIS_IGBP land-use definitions

- Run 5 high-resolution nested domains inside the 12km NAM every cycle. These nests will run with greatly reduced convective triggering, which improved quantitative precipitation forecast (QPF) bias compared to using explicit convection.

NDAS Changes:

- Initial first guess at T-12hr will reflect relocation of tropical cyclones

- Will use 1/12 degree high resolution real-time sea surface temperature (RTG_SST_HR) analysis instead of the 1/2th degree real-time SST analysis.

Changes to the Gridscale Statistical Interpolation (GSI) analysis:

- Assimilation of new observations: ACARS humidity, Windsat and ASCAT (superob'ed Scatterometer winds over oceans), HIRS radiances from NOAA-19, AMSU-A radiances from NOAA-19 and AQUA, IASI radiances from METOP, GPS radio occultation refractivity (COSMIC), RASS virtual temperatures, MAP (boundary layer profiler) winds and MESONET surface pressure/temperature/ humidity (winds already included)

Changes to the NAM post-processing code:

- All Convective Available Potential Energy (CAPE), Convective Inhibition (CIN), and Lifted Index (LI) variables in the NAM output will be computed using virtual temperature instead of sensible temperature. See the NWS Public Information Statement issued January 12, 2011 for more details on this change.

[triadwx]

I guess so. The models keep trending south with more and more snow, even at RDU, but RAH still doesn't seem ready to pull the trigger yet, The totals they are talking about seem to be a lot lower than the latest model runs show and what others on here, even mets, have said.

It'll likely come tonight or early tomorrow, if the models keep up what they're showing, and I have no doubt that they will. We all know how RAH operates, they are very conservative.

[beanskip]

Correction on 18z RGEM precip -- b/w maps fooled me -- it really just smoothed out QPF. More coverage of 10mm+, but some of the higher total over Tenn. are cut back.

[SBUWX23]

Thanks! I was close! I actually use the WRF in my graduate research so I recalled the NAM had something to do with the WRF

Here is some information on the most recent NAM upgrade:

NCEP will introduce the use of the new NOAA Environmental Modeling System (NEMS), which is based on the tenets put forth by the Earth System Modeling Framework to which NOAA has subscribed. Eventually all of NCEP’s major modeling will be performed within NEMS. This NAM upgrade represents the first implementation of NEMS and a major step in the evolution of NCEP’s modeling suite.

The prediction model used in the NAM run will go from being the strictly regional Nonhydrostatic Mesoscale Model (NMM) to a new extended capability version now known as Nonhydrostatic Multiscale Model on B-grid (NMMB), which can be run either regionally or globally, and with or without embedded nests. This NEMS-NMMB will also serve as the prediction model running in the NAM Data Assimilation System (NDAS). Some of the model changes/ enhancements in the NEMS-NMMB include:

- Native horizontal grid is an Arakawa staggered B-grid (rotated 45 deg from the Arakawa E-grid in the WRF-NMM NAM)

- Modified vertical level distribution with more layers in the stratosphere (14 layers above 200 mb instead of 7 in the current operational NAM)

- Microphysics changes to produce higher peak reflectivities above 45 dBZ with higher peak surface rainfall rates in the high-resolution nests and more realistic grid-scale cloud fractions from cold, high cirrus.

- Change from USGS to MODIS_IGBP land-use definitions

- Run 5 high-resolution nested domains inside the 12km NAM every cycle. These nests will run with greatly reduced convective triggering, which improved quantitative precipitation forecast (QPF) bias compared to using explicit convection.

NDAS Changes:

- Initial first guess at T-12hr will reflect relocation of tropical cyclones

- Will use 1/12 degree high resolution real-time sea surface temperature (RTG_SST_HR) analysis instead of the 1/2th degree real-time SST analysis.

Changes to the Gridscale Statistical Interpolation (GSI) analysis:

- Assimilation of new observations: ACARS humidity, Windsat and ASCAT (superob'ed Scatterometer winds over oceans), HIRS radiances from NOAA-19, AMSU-A radiances from NOAA-19 and AQUA, IASI radiances from METOP, GPS radio occultation refractivity (COSMIC), RASS virtual temperatures, MAP (boundary layer profiler) winds and MESONET surface pressure/temperature/ humidity (winds already included)

Changes to the NAM post-processing code:

- All Convective Available Potential Energy (CAPE), Convective Inhibition (CIN), and Lifted Index (LI) variables in the NAM output will be computed using virtual temperature instead of sensible temperature. See the NWS Public Information Statement issued January 12, 2011 for more details on this change.

[chapelhillwx]

not yet, they said most likely

Meant to type "WWAs likely" but I'll edit that

[burgertime]

18z GFS looks further south and slower with that second piece of energy...starts to phase @21

[calculus1]

Surface at hour 30 on 18Z GFS:

[WinterWonderland]

Carver...yes, they are usually more conservative, but after reading the forum all day, was still surprised they didn't have us at least in the 1-3 range.?!?

It's also puzzling to me that Morristown does not issue ANYTHING for the valley. I can see them not expecting much snow with the warm nose and all therefore not issuing an advisory, but to not even issue a hazardous outlook or special weather statement is odd to me. Maybe they're not expecting any snow in our area at all.

[burgertime]

lol little slug of moisture breaks away just east of CLT...man if that could sit over CLT we would be in business on this run!