Texas winter wx thread (2009-2010)

[cycloneye]

I think that won't be the only winter weather event you see this year. More to come!!

Especially with the El Nino holding its own in a moderate to strong status.

[Portastorm]

I think that won't be the only winter weather event you see this year. More to come!!

Especially with the El Nino holding its own in a moderate to strong status.

Indeed ... and thanks for keeping us posted with those Nino indices. Appreciate it!

Between the moderate to strong Nino and an Arctic Oscillation strongly in negative numbers ... bodes well for a cold and stormy period continuing.

[txagwxman]

Interesting forecast Tue...may see some sleet NW of Houston in the morning, then change to rain.
DFW snow now, thickness lower...Question remains on the New Year's eve system...GFS only run that has it, ECMWF ensembles have the trough further east, and suggest cold sunny weather for Texas for New Year's weekend.

[gofrogs]

Iam looking at the fourth through the seveenth that time period looks very intersting for at leat ntx.

[Portastorm]

12z NAM is still looking good for North Texas ... a little warmer for south central Texas (crud!) for the Tuesday event. Isentropic lift events usually provide good, spread-out precip shields.

Incidentally, the 0z NAM suggested a 2-3 inch snowfall for the DFW Metroplex while the 0z GFS showed amounts from a trace up to an inch. The link below is a great mapping tool that shows both the GFS and NAM snowfall totals. It usually updates only for the 0z and 12z runs. The "snow overlay" tools are what you will want to use.

http://www.wxcaster.com/models_main.htm

[srainhoutx]

Appears the NAM keeps the disturbance as an open wave...we shall see...

http://www.nco.ncep.noaa.gov/pmb/nwprod ... loop.shtml

WV Imagery shows the disturbance heading toward S CA/Baja at a fairly good clip...remember that little sampling other than satellite and perhaps some ship and aircraft obs are injested into the data set...

http://wxweb.meteostar.com/models/noaap ... UMBLOOP=10

Also, we need to keep an eye on what may occur beyond the Pre New Years storm. There are indications that some mighty chilly air will settle into the region with a noisy STJ and embedded shortwave activity in the N/NW flow.

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
859 AM EST SUN DEC 27 2009

VALID 12Z THU DEC 31 2009 - 12Z SUN JAN 03 2010

TELECONNECTIONS WITH A NEGATIVE ANOMALY...THE POLAR VORTEX...OVER
THE WESTERN CANADIAN ARCHIPELAGO FAVOR TROUGHING ACROSS EASTERN
CANADA AND THE NORTHEAST AS WELL AS A SOUTHERN STREAM TO THE
WESTERLIES NEAR THE US/MEXICAN BORDER. THE MODELS GENERALLY FAVOR
THESE IDEAS.

PERHAPS EQUALLY IMPORTANT TO THE OVERALL PATTERN IS THE
REDEVELOPMENT OF VERY STRONG BLOCKING OVER SRN GREENLAND BY THU
THAT DRIFTS SLOWLY WWD INTO THE SRN DAVIS STRAIT NEXT WEEKEND.
THIS STRONG HIGH LATITUDE BLOCK FAVORS SUPPRESSED WESTERLIES
ACROSS THE LOWER 48 STATES WELL EWD INTO THE ATLANTIC. THESE
SUPPRESSED WESTERLIES..JOINING FORCES WITH THE SRN STREAM NEAR THE
US/MEXICAN BORDER AND THE MODERATE EL NINO...FAVOR AN ACTIVE STORM
TRACK ACROSS THE GULF OF MEXICO TOWARDS THE S ATLANTIC COAST.

IN THE EASTERN HALF OF THE COUNTRY...THE ECMWF CONTINUES TO WAVER
A BIT CONCERNING THE TIMING OF THE FRONTAL WAVE/COASTAL LOW
EXPECTED TO MOVE FROM THE GULF OF MEXICO UP THE SOUTHEAST COAST TO
NEAR THE 40N/70W BENCHMARK...WITH ITS MOST RECENT RUN ON THE FAST
SIDE OF ITS PAST 36 HOURS OF RUNS THOUGH SIMILAR TO THE TIMING
SEEN ON ITS RUNS FROM 2-3 DAYS AGO.

ALTHOUGH THE 12Z MULTI-MODEL ENSEMBLE LOW MEMBERS WERE TIGHTENING
UP THEIR DISTRIBUTION SOMEWHAT /SLIGHTLY OUTPACING THE OPERATIONAL
00Z ECMWF EARLY ON/...THERE CONTINUES TO BE TIMING ISSUES WITH THE
GEFS MEMBERS GENERALLY SHOWING QUICKER SOLUTIONS THAN THE ECMWF
MEMBERS. WHEN THIS OCCURS...THE OPTIMAL LOCATION FOR LOW
PLACEMENT IS THE FAST SIDE OF THE ECMWF/SLOW SIDE OF THE GEFS
ENSEMBLE MEMBER SPREAD. THIS COMPROMISE WAS USED AS THE BASELINE
FOR THE PRESSURES. SMALL REFINEMENTS WERE MADE PER THE ENSEMBLE
GUIDANCE AS WELL AS TO TIGHTEN UP PRESSURE/WIND GRADIENTS. THE
POTENTIAL EAST COAST SYSTEM PORTENDS MORE SNOW TO THE MID-ATLANTIC
AND NEW ENGLAND STATES THU/FRI. THE GENERAL LARGE SCALE FLOW
PATTERN SURROUNDING ITS EVOLUTION AND STEERING SHOWS SOME
RESEMBLANCE TO THE LAST SNOWSTORM IMPACTING THE REGION JUST OVER A
WEEK AGO.

THE 06Z/27 GFS IS DROPPING A STRONG PIECE OF ARCTIC ENERGY WELL S
INTO THE UPPER OH VLY BY DAY 6 SAT. IF CORRECT...THIS UPPER
FEATURE COULD BE STRONG ENOUGH TO INDUCE COLD AIR DEVELOPMENT
BEHIND THE MAIN SYS WHICH WILL ALREADY BE OFFSHORE EARLY IN THE
WEEKEND....REJUVENATING SNOWFALL OVER NEW ENG. THE 06Z/27 GFS RUN
IS A WESTERN OUTLIER WITH THE ARCTIC ENERGY...BUT IS JUST A BIT W
OF THE ECMWF WITH THE SAME FEATURE. WE WILL WATCH THIS EVOLUTION
OF THIS ARCTIC SYS ON NEW 12Z MODEL RUNS. ENSEMBLE SPAGHETTI
PLOTS FAVOR A LESS AMPLIFIED MORE PROGRESSIVE SOLUTION TO THIS
UPPER FEATURE NEXT WEEKEND.
IN THE WEST...CONFIDENCE IS LOWEST IN THE EXPECTED FLOW PATTERN
NEXT WEEKEND AS THE DETERMINISTIC GUIDANCE SHOWS TROUGHING INTO
THE REGION WHICH IS SOMEWHAT OUT OF SYNC WITH THE 00Z GEFS/12Z
ECMWF ENSEMBLE MEANS WHICH SHOW FLAT FLOW OR WEAK RIDGING ACROSS
THE NORTHWEST AND SOUTHWEST CANADA.

ROTH/FLOOD

[msstateguy83]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.

here we go again? iam not so sure of that but after looking @ the gfs models and liquid precip amts we could
be seeing on the (HIGH END) of things up to around 6-8 inches of snow across portions of northwest, west
central tx, i would say maybe 2-3 inches across the metroplex region of dallas-fortworth with poss some 4
inch amounts on the western side of the metroplex say west of i-35 w from ft worth denton area & points
west of that to around decatur, weatherford possibly over to mineral wells.

to me this system looks even more impressive then say just this time yesterday, it bares watching
very,very closely. if i wanted to but iam not willing to go that far yet i would bump these amts of
snow up, but iam not that sure yet however models under estimated precip amounts for the most
part last go around so is it possible this time? iam sure it is, question is are they currently?

stay tuned i will post more thoughts later

[srainhoutx]

SWS from Midland/Odessa...

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MIDLAND/ODESSA TX
604 AM CST SUN DEC 27 2009

NMZ027>029-033-034-TXZ045>048-050>053-057>063-067>070-074-075-
079>082-258-272200-
GUADALUPE MOUNTAINS OF EDDY COUNTY-EDDY COUNTY PLAINS-
NORTHERN LEA COUNTY-CENTRAL LEA COUNTY-SOUTHERN LEA COUNTY-GAINES-
DAWSON-BORDEN-SCURRY-ANDREWS-MARTIN-HOWARD-MITCHELL-
VAN HORN AND HIGHWAY 54 CORRIDOR-
REEVES COUNTY AND UPPER TRANS PECOS-LOVING-WINKLER-ECTOR-MIDLAND-
GLASSCOCK-WARD-CRANE-UPTON-REAGAN-DAVIS/APACHE MOUNTAINS AREA-
PECOS-PRESIDIO VALLEY-MARFA PLATEAU-BIG BEND AREA-TERRELL-
GUADALUPE MOUNTAINS-
INCLUDING THE CITIES OF...QUEEN...ARTESIA...CARLSBAD...
CARLSBAD CAVERNS NP...TATUM...HOBBS...LOVINGTON...EUNICE...JAL...
SEMINOLE...LAMESA...GAIL...SNYDER...ANDREWS...STANTON...
BIG SPRING...COLORADO CITY...VAN HORN...PECOS...MENTONE...
RED BLUFF LAKE...KERMIT...ODESSA...MIDLAND...GARDEN CITY...
MONAHANS...CRANE...MCCAMEY...RANKIN...BIG LAKE...ALPINE...
FORT DAVIS...FORT STOCKTON...PRESIDIO...MARFA...BIG BEND NP...
MARATHON...SANDERSON...GUADALUPE MOUNTAINS NP...PINE SPRINGS
604 AM CST SUN DEC 27 2009 /504 AM MST SUN DEC 27 2009/

...ACCUMULATING SNOWFALL POSSIBLE FOR WEST TEXAS AND SOUTHEASTERN
NEW MEXICO MONDAY NIGHT AND TUESDAY...

ANOTHER SURGE OF COOLER AIR WILL MOVE INTO THE REGION ON MONDAY.
AS THE COLD AIR CONTINUES TO SETTLE SOUTHWARD MONDAY NIGHT...
TEMPERATURES WILL DROP BELOW FREEZING FOR MOST AREAS. MEANWHILE...
AN UPPER LEVEL STORM SYSTEM WILL GAIN STRENGTH ACROSS NORTHERN
MEXICO. AS THIS STORM SYSTEM MOVES ACROSS WEST TEXAS AND
SOUTHEASTERN NEW MEXICO MONDAY NIGHT AND TUESDAY...WINTRY
PRECIPITATION...MAINLY IN THE FORM OF SNOW...IS EXPECTED.
UNCERTAINTY EXISTS WITH REGARD TO THE TIMING AND AMOUNT OF
SNOWFALL...BUT ANYWHERE FROM 1 TO 3 INCHES OF SNOW COULD
ACCUMULATE MONDAY NIGHT INTO TUESDAY MORNING. AT THE PRESENT
TIME... THE BIG BEND REGION...LOWER TRANS PECOS AND STOCKTON
PLATEAU ARE FAVORED FOR THE HEAVIER SNOWFALL AMOUNTS. THE
WINTRY PRECIPITATION IS EXPECTED TO SHIFT EAST OF THE AREA TUESDAY
NIGHT.

San Angelo...

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN ANGELO TX
508 AM CST SUN DEC 27 2009

TXZ049-054-064>066-071>073-076>078-098-099-113-114-127-128-139-
140-154-155-168>170-272200-
FISHER-NOLAN-STERLING-COKE-RUNNELS-IRION-TOM GREEN-CONCHO-
CROCKETT-SCHLEICHER-SUTTON-HASKELL-THROCKMORTON-JONES-SHACKELFORD-
TAYLOR-CALLAHAN-COLEMAN-BROWN-MCCULLOCH-SAN SABA-MENARD-KIMBLE-
MASON-
INCLUDING THE CITIES OF...ROTAN...ROBY...SWEETWATER...
STERLING CITY...ROBERT LEE...BRONTE...BALLINGER...WINTERS...
MERTZON...SAN ANGELO...EDEN...OZONA...ELDORADO...SONORA...
HASKELL...THROCKMORTON...WOODSON...STAMFORD...ANSON...HAMLIN...
ALBANY...ABILENE...CLYDE...BAIRD...CROSS PLAINS...COLEMAN...
BROWNWOOD...BRADY...SAN SABA...MENARD...JUNCTION...MASON
508 AM CST SUN DEC 27 2009

...ANOTHER POTENTIAL WINTER STORM IN STORE FOR WEST CENTRAL TEXAS ON
TUESDAY....

THE POTENTIAL FOR ANOTHER WINTER STORM IS INCREASING FOR PORTIONS OF
WEST CENTRAL TX ON TUESDAY. AN UPPER DISTURBANCE WILL APPROACH THE
REGION FROM THE WEST. AHEAD OF THE SYSTEM...WARM...MOIST AIR WILL BE
LIFTED UP AND OVER COLD AIR IN PLACE AT THE SURFACE TO PRODUCE SNOW.
SIGNIFICANT ACCUMULATION OF SNOW IS POSSIBLE MAINLY SOUTH OF
INTERSTATE 20 WHICH COULD IMPACT TRAVEL. STAY TUNED TO THE LATEST
FORECAST UPDATES.

[Portastorm]

For the Monday night-Tuesday event, the 12z GFS supresses most of the energy to south Texas which would limit precip amounts in the northern part of the state to "light." Central, South, and Southeast Texas look to pick up at least a half inch of liquid per the model run but unfortunately the temps will be too warm for much, if any, winter "fun."

Maybe the 12z Euro and CMC will give us a colder look.

[msstateguy83]

The following post is NOT an official forecast and should not be used as such. It is just the opinion of the poster and may or may not be backed by sound meteorological data. It is NOT endorsed by any professional institution including storm2k.org. For official information, please refer to NWS products.


just my opinion but i STRONGLY do not buy into the 12z gfs which as stated pushes most of the energy into south tx...

[Ntxw]

Looks like all snow up here, I was getting worried last night it could turn out to be a frzing rain\sleet event. And should it remain and open wave, I don't believe the moisture would all stay south. However, should a strong coastal low form, it might pull all the moisture southwards with it.

Edit: FW nws has put up a special weather statement for accumulating snow

[gboudx]

Looks like all snow up here, I was getting worried last night it could turn out to be a frzing rain\sleet event. And should it remain and open wave, I don't believe the moisture would all stay south. However, should a strong coastal low form, it might pull all the moisture southwards with it.

Edit: FW nws has put up a special weather statement for accumulating snow

Here's the SPS. I'm expecting us out on the east side to get "jipped" again. We got about 1/2" Xmas Eve, while most everyone else got an inch or more. At least we're not like Portastorm.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
1022 AM CST SUN DEC 27 2009

TXZ091>095-100>107-115>123-129>135-141>146-156-157-159-280100-
MONTAGUE-COOKE-GRAYSON-FANNIN-LAMAR-YOUNG-JACK-WISE-DENTON-COLLIN-
HUNT-DELTA-HOPKINS-STEPHENS-PALO PINTO-PARKER-TARRANT-DALLAS-
ROCKWALL-KAUFMAN-VAN ZANDT-RAINS-EASTLAND-ERATH-HOOD-SOMERVELL-
JOHNSON-ELLIS-HENDERSON-COMANCHE-MILLS-HAMILTON-BOSQUE-HILL-
NAVARRO-LAMPASAS-CORYELL-MCLENNAN-
1022 AM CST SUN DEC 27 2009

...WINTER WEATHER TO RETURN TO PARTS OF NORTH TEXAS TUESDAY AND
TUESDAY NIGHT...

A COLD...POLAR AIRMASS WILL REMAIN ENTRENCHED ACROSS NORTH TEXAS
THROUGH THE COMING WEEK. A STORM SYSTEM WILL APPROACH TUESDAY AND
MOVE ACROSS THE AREA TUESDAY NIGHT. INITIAL PRECIPITATION FALLING
THROUGH THE DRY AND COLD LOW LEVEL AIR TUESDAY MORNING WILL HELP
COOL AND SATURATE THE ATMOSPHERE FOR THE POTENTIAL OF A LIGHT RAIN
AND SNOW MIX. THE WINTRY MIX IS EXPECTED TO IMPACT AREAS NORTH OF
A LAMPASAS...WACO...ATHENS LINE THROUGH MIDDAY TUESDAY. BY TUESDAY
AFTERNOON AND EVENING...THE PRECIPITATION WILL LIKELY CHANGE OVER
TO ALL SNOW NORTH OF A COMANCHE...WAXAHACHIE... EMORY LINE.
ACCUMULATIONS OF ONE TO TWO INCHES APPEAR POSSIBLE...PARTICULARLY
WEST OF INTERSTATE 35.

IT APPEARS AREAS ALONG AND SOUTHEAST OF TEMPLE TO PALESTINE LINE
WILL REMAIN WARM ENOUGH FOR THE PRECIPITATION TO REMAIN IN THE FORM
OF A COLD RAIN.

MANY UNCERTAINTIES REMAIN CONCERNING MOISTURE AVAILABILITY AND THE
STRENGTH OF THE SYSTEM. IF THE SYSTEM APPEARS STRONGER AND THERE IS
MORE AVAILABLE MOISTURE...THEN EXPECTED SNOW AMOUNTS COULD INCREASE.
PLEASE MONITOR FUTURE FORECASTS REGARDING CHANGES TO THE TRACK AND
INTENSITY OF THE STORM SYSTEM EXPECTED ON TUESDAY...AS MORE RELIABLE
INFORMATION BECOMES AVAILABLE TO FORECASTERS.

[Ntxw]

The last snow event I think has set up the ground temperatures pretty chilly along with a freeze every night since then, a few of them hard freezes. Things should stick nicely

[gofrogs]

Any later highlights on the new gfs for the first eek of january or new years eve.

[Ntxw]

12z does show some snow possibilities around new years, gfs has been rather bullish as of late with moisture and track. The cold cold stuff on this run seems to be shunted more east after new years.

[gofrogs]

Yeah but thats just one run, theres been zero consistencity with the gfs outside of five days in my opinion. I mean the last storm did nt show back up till two days out so well see just wait and see.

[Ntxw]

Yeah but thats just one run, theres been zero consistencity with the gfs outside of five days in my opinion. I mean the last storm did nt show back up till two days out so well see just wait and see.

Yup, the cold has been on and off in the models, the EC is trending mighty cold and usually that model is better for further out. This is what FW says for that period.

FINALLY...A LOOK BEYOND THIS FORECAST PERIOD SUGGESTS WE WILL NEED
TO KEEP AN EYE ON THE FATE OF AN EXTREMELY COLD AIRMASS THAT
WILL BE ORGANIZING IN NORTHERN CANADA. GFS/ECMWF FOR SEVERAL DAYS
HAVE BEEN BRINGING A POLAR VORTEX FROM SIBERIA ACROSS THE NORTH
POLE INTO THE CANADIAN ARCHIPELAGO. GFS KEEPS THE COLD AIR BOTTLED
UP...BUT THE ECMWF FOR A COUPLE DAYS HAS BEEN INDICATING A GOOD
UPPER PATTERN TO ALLOW THIS AIRMASS SOUTHWARD JAN 5-8. LAST RUN OF
THE ECMWF HAS A SURFACE HIGH OF 1066MB NORTH OF ALASKA...WHICH IS
THE HIGHEST I HAVE EVER SEEN THAT MODEL FORECAST.

[gofrogs]

I like this storm to lol, but iam also really liking the time frame around new years eve preferabbly after, forthat first week. GFS has been consitent with the precip in that frame constitlenally in 6 to 8 10ths of an inch for dfw. The other models which are better for this time frame are suggesting the cold very cold air to come down, well see but the gfs is signifficantly undercutting the temperatures. Tuesday storm for dfw iam calling for any where from 2- to an isolated 4.

[Ntxw]

By the way, just about all of the big cities in Texas (Except perhaps Austin, San Antonio, and Amarillo) have gotten their yearly averages for snow. Just about safe to say this could be above normal for snowfall?

Edit: When would the watches and advisories be posted up for the event?

[srainhoutx]

Another system that contains a lot of unertainty. Just a reminder, this event is unlike the Pre Christmas storm. This feature is heading in from S CA/Baja and traveling E versus the Pacific NW and diving S along the trough that brought the previous storm/snow to N and W TX/OK and the Plains.

MODEL DIAGNOSTIC DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
1224 PM EST SUN DEC 27 2009

VALID DEC 27/1200 UTC THRU DEC 31/0000 UTC

...SEE NOUS42 KWNO ADMNFD FOR THE STATUS OF THE UPPER AIR
INGEST...


12Z MODEL EVALUATION INCLUDING THE UKMET/CANADIAN GLBL


MODEL INITIALIZATION ERRORS DO NOT APPEAR TO HAVE A SIGNIFICANT
IMPACT ON THE SHORT RANGE FORECAST.


...SYSTEM NEARING THE PAC NW COAST ON TUE...

PREFERENCE: GFS/NAM COMPROMISE 2/3 TOWARD THE GFS

THE GFS IS GENERALLY FASTER AND MORE AMPLIFIED THAN THE NAM WITH
THIS SYSTEM... THOUGH THE NAM/GFS NEARLY CONVERGE WITH THE SFC LOW
LINGERING OFF THE PAC NW COAST THRU WED. OTHER MODEL AND ENSEMBLE
GUIDANCE IS NOT WELL CLUSTERED BUT 12Z MODELS SEEM TO BE
DEVELOPING A CONSENSUS OVER THE WEST BY WED. THE 00Z ECMWF/ECMWF
ENSEMBLE MEAN ARE THE SLOWEST SOLNS WITH THE CORE OF MID LVL
ENERGY REMAINING OFF THE PAC NW COAST BY WED AND LEAST AMPLIFIED
WITH THE ENERGY THAT PROGRESSES INTO THE WEST ON WED. THE 12Z
UKMET/CMC CLUSTER NEAR THE FASTER GFS WITH ENERGY PROGRESSING INTO
THE WEST... AND SHOW SIMILAR AMPLITUDE AS WELL. AS FOR NAM/GFS
TRENDS OVER THE PAST DAY... THE NAM HAS TRENDED FASTER/MORE
AMPLIFIED WITH THE TROF AS IT NEARS THE WEST COAST BUT WITH SOME
VARIABILITY ON TIMING OF THE EMBEDDED UPPER LOW. THE GFS HAS
TRENDED MORE AMPLIFIED NEARING THE COAST BUT THEN SLOWER AND/OR
LESS AMPLIFIED AS THE TROF CONTINUES OVER THE WEST. THE GFS IS A
LITTLE EXTREME WITH THE SEWD AMPLITUDE OF AN UPSTREAM PAC SYSTEM
BY LATE WED SO GFS SPECIFICS ARE IN QUESTION... BUT SHARPENING OF
THE INTERVENING RIDGE DOES SUPPORT MORE WRN CONUS AMPLIFICATION
THAN FCST BY THE 00Z ECMWF. PREFER A GFS/NAM COMPROMISE 2/3
TOWARD THE GFS.


...SRN STREAM TROF REACHING THE PLAINS BY WED...

PREFERENCE: GFS/NAM COMPROMISE

THE GFS IS FASTER THAN THE NAM WITH BOTH SIGNIFICANT PARTS OF THIS
TROF... THE LEADING ENERGY REACHING THE PLAINS BY TUE AND TRAILING
ENERGY REACHING THE PLAINS ON WED. THE CURRENT MODEL/ENSEMBLE
SPREAD INCLUDING 12Z UKMET/CMC FAVORS A COMPROMISE TIMING WITH
LEADING ENERGY WHILE THERE IS ENOUGH SPREAD TO INCLUDE BOTH NAM
AND GFS SOLNS WITH TRAILING ENERGY BY WED. SPECIFICALLY BY F84
LATE WED THE 06Z GEFS MEAN IS ALMOST AS FAST AS THE 12Z GFS ALOFT
AND IDENTICAL TO THE GFS WITH THE GULF COAST SFC LOW... WHILE THE
00Z UKMET AND ECMWF/EC MEAN ARE SIMILAR TO THE NAM. THE UKMET/CMC
ARE GENERALLY BETWEEN THE GFS/NAM... THOUGH TIMING IS CLOSER TO
THE NAM WITH THE GULF COAST SFC LOW BY LATE WED... UKMET A LITTLE
NWD AND CMC SWD. THE 12Z GFS HAS ADJUSTED SLOWER FROM OUTLIER
FAST SOLNS IN THE 06Z/00Z RUNS WITH THE SFC WAVE BUT PAST 12 HRS
OF GFS RUNS HAVE BEEN STABLE ALOFT. LONGER TERM TRENDS OF THE
NAM/GFS HAVE BEEN LEANING GRADUALLY FASTER. CURRENT GUIDANCE
SPREAD COMBINED WITH OBSERVED TRENDS FAVOR A COMPROMISE APPROACH
HALFWAY BETWEEN THE GFS AND NAM... WITH SOME ELEMENTS OF THE 00Z
ECMWF ALSO A REASONABLE COMPONENT OF THE PREFERRED SOLN.

...WEAKENING SYSTEM OFF THE PAC NW COAST SUN-MON...

MINOR DETAIL DIFFS STILL EXIST BUT OVERALL THE 12Z MODELS/00Z
ECMWF DISPLAY GOOD CLUSTERING... FAVORING A BLEND OF LATEST
GUIDANCE.


...US-CANADIAN BORDER LOW PRESSURE TUE-WED...

PREFERENCE: AVERAGE OF GFS/NAM SOLNS

THE NAM/GFS DISPLAY SIMILAR SOLNS WITH ONLY MINOR TIMING/DETAIL
DIFFS. THE 00Z ECMWF ENSEMBLE MEAN SUGGESTS THE OPERATIONAL ECMWF
MAY BECOME A LITTLE TOO AMPLIFIED WITH SRN CANADA/NRN PLAINS FLOW
BY WED... AND CONSENSUS INDICATES UPSTREAM FLOW IN THE ECMWF COULD
BE TOO FLAT... SO CONFIDENCE IS MODEST IN THE FASTER 00Z ECMWF SFC
FRONT EXTENDING SWWD FROM THE SFC WAVE ON WED. ON THE OTHER HAND
THE CANADIAN GLBL RUNS HAVE BEEN ERRATIC WITH SRN CANADA/NRN CONUS
FLOW LATE IN THE PERIOD SO CONFIDENCE IS LOW IN ITS SFC LOW THAT
IS ON THE SWRN EDGE OF THE GUIDANCE SPREAD BY LATE WED. BEST
GUIDANCE CLUSTERING SUGGESTS A BLEND AMONG THE GFS/NAM SHOULD
PROVIDE A REASONABLE FCST.


...TROF AMPLIFYING INTO THE GRTLKS/NORTHEAST MON-TUE...

PREFERENCE: UKMET/CANADIAN GLBL/00Z ECMWF

THE NAM IS MORE AMPLIFIED/DEEPER VERSUS THE GFS FROM MON ONWARD.
THE NAM HAS A TENDENCY TOWARD EXCESSIVELY DEEP TROFS. HOWEVER
REASONABLE CONTINUITY IN THE NAM OVER THE PAST DAY... A VERY
SLIGHT DEEPENING TREND IN THE GFS... AND A SOMEWHAT DEEPER THAN
GFS SOLN IN THE UKMET/CANADIAN GLBL/00Z ECMWF... OFFER SUPPORT FOR
AN INTERMEDIATE SOLN BETWEEN THE NAM AND GFS EXTREMES. THUS
PREFER THE UKMET/CMC/00Z ECMWF.


...UPPER LOW DEPARTING FROM THE MS VALLEY/GRTLKS...

PREFERENCE: GFS

THE NAM AND GFS ARE SIMILAR WITH THE DEPARTING UPPER LOW BUT THE
GFS GRADUALLY TRENDS E/NE OF THE NAM WITH DEEPENING LOW PRESSURE
FCST TO TRACK FROM THE COAST OF MAINE INTO THE CANADIAN MARITIMES.
STRONG CONSENSUS OF 00Z MODELS... LATEST ENSEMBLE MEANS... AND
12Z UKMET/CANADIAN GLBL AND REG GEM FAVOR A SFC TRACK EVEN FARTHER
E THAN THE GFS BY F48 EARLY TUE. THIS RELATIVE CLUSTERING
CONTRASTS TO SLOWER TRENDS SEEN IN THE GFS/NAM OVER THE PAST DAY.
UKMET/CMC/ECMWF PREFERENCE WITH UPSTREAM FLOW AMPLIFYING INTO THE
NORTHEAST WOULD FAVOR LEANING A LITTLE EWD OF THE GFS BUT AT THIS
TIME PREFER TO GIVE AT LEAST SOME WEIGHTING TO GFS/NAM TRENDS AND
THUS WILL RECOMMEND THE GFS.

RAUSCH

...MODEL TREND GRAPHICS AT
http://WWW.HPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML...

...500MB FORECASTS AT http://WWW.HPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML...