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POST-CHRISTMAS SNOW FOR DALLAS AND ARKLATEX - Printable Version

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POST-CHRISTMAS SNOW FOR DALLAS AND ARKLATEX - Joe-Nathan - 12-17-2012 03:37 PM

Well this could be interesting if it pans out:

[Image: GFS_3_2012121712_F228_SNOWIN_SURFACE.png]


POST-CHRISTMAS SNOW FOR DALLAS AND ARKLATEX - Joe-Nathan - 12-18-2012 07:47 AM

STILL THERE...BUT NOT AS FAR SOUTH AND ABOUT 12hr LATER:
[Image: GFS_3_2012121806_F228_SNOWIN_SURFACE.png]

[Image: GFS_3_2012121806_F228_TMPF_2_M_ABOVE_GROUND.png]


POST-CHRISTMAS SNOW FOR DALLAS AND ARKLATEX - Joe-Nathan - 12-19-2012 08:10 AM

Alright so the Christmas Front is going to be a good one, except for me. All I will get is rain:

[Image: GFS_3_2012121906_F192_SNOWIN_SURFACE.png]


NOW THE NEW YEAR LOOKS MORE PROMISING FOR SOME DEEP SOUTH SNOW ACTION...


POST-CHRISTMAS SNOW FOR DALLAS AND ARKLATEX - ROLLTIDE - 12-21-2012 09:57 AM

If you want snow for xmas it looks like Little Rock would be a good place to go Smile


POST-CHRISTMAS SNOW FOR DALLAS AND ARKLATEX - ROLLTIDE - 12-23-2012 03:44 PM

[Image: image1.gif]


POST-CHRISTMAS SNOW FOR DALLAS AND ARKLATEX - BAMAMAMA1964 - 12-23-2012 04:16 PM

I SO WISHED FOR SNOW,LOL..!!


POST-CHRISTMAS SNOW FOR DALLAS AND ARKLATEX - Joe-Nathan - 12-23-2012 04:25 PM

CHRISTMAS DAY:

[Image: noaad3.gif]

HPC DAY 2:
[Image: day2_psnow_gt_04.gif]

HPC DAY 3:
[Image: day3_psnow_gt_04.gif]


POST-CHRISTMAS SNOW FOR DALLAS AND ARKLATEX - Joe-Nathan - 12-23-2012 04:30 PM

HPC DAY 3 WINTER DISCO:

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
500 AM EST SUN DEC 23 2012


Quote:...DAY 3...

...PAC NW/CA...

AN AMPLIFYING...SLOW MOVING LOW-MID LEVEL CYCLONE GRADUALLY MOVES
EAST OVER THE NORTH PACIFIC. THE CYCLONE IS PRECEDED BY A SWATH OF
850-700 MB THETA-E ADVECTION AND CONVERGENCE ACROSS THE COASTAL
RANGES OF WA-OR AND THEN EXTENDING INLAND INTO THE CASCADES. A
SUSTAINED PERIOD OF UPPER DIVERGENCE IN THE VICINITY OF A JET MAX
OCCURS ACROSS NORTHERN OR AND WESTERN WA. GIVEN THAT THIS WAVE
WILL BE SHORTER IN WAVELENGTH (MORE AMPLIFIED)...THE DEGREE OF
LONG-FETCH...DEEP LAYER MSTR POOLING OFF THE PAC WILL BE LESS THAN
WITH PRIOR WAVES...AS 850-700 MB MSTR FLUX CONVERGENCE ANOMALIES
PER THE SREF AND GEFS ARE CLOSER TO 1 STD DEV ABOVE NORMAL
COMPARED TO THE 2-3 STD DEVS ABOVE THE NORM WITH THE SYSTEM LATER
TODAY AND TONIGHT. HIGHER SNOW LEVELS WILL LIMIT THE EXTENT OF 12+
INCH AMOUNTS ACROSS THE SIERRAS...BOTH W-E AS WELL AS N-S...THOUGH
AT THE SAME TIME GIVEN LOWER SNOW LEVELS AND MORE ROBUST
FORCING/VERTICAL MOTION...AMOUNTS ACROSS THE OR AND SRN WA
CASCADES COULD EXCEED ONE FOOT.

...PTNS OF THE SRN PLAINS INTO THE LOWER MS VLY/WRN TN VLY/LOWER
OH VLY...

THE ELONGATED SHORTWAVE AFFECTING THE W COAST ON DAY ONE...THEN
THE IM REGION/ROCKIES ON DAY 2...WILL DIG SE ACROSS THE SRN PLAINS
AND EVENTUALLY LIFT ENE ACROSS THE LOWER MS VLY AND INTO THE
TN/LWR OH VLYS BY THE END OF DAY 3. HPC'S SNOW/ICE PROBABILITIES
WERE BASED ON A BLENDED APPROACH BOTH WITH THE QPF AND THERMAL
STRUCTURES...AS PER THE PMDHMD...THE ENSEMBLE WAS INITIALLY
NON-GFS BASED GIVEN THE RELATIVE FAST SPEED OF THE GFS COMPARED TO
THE OTHER MODEL CLUSTERS. THE 06Z GFS HAS ESSENTIALLY COME IN
BETTER ACCORD WITH THE LATEST NAM IN TERMS OF THE SFC LOW TRACK
FROM NRN LA TO NRN MS...CEN TN...AND ACROSS CEN KY TOWARD THE END
OF DAY 3 (12Z 12/26). THE ECMWF AND UKMET REMAIN SLOWER WITH THE
LOW TRACK...AND ESSENTIALLY FARTHER S (CEN TN) WITH THE LOW BY 12Z
12/26 OR WED MORNING. GIVEN THE TIMING DIFFS BTWN THE NECP CAMP
AND THE ECMWF/UKMET...AGAIN FOR NOW HPC USED AN ENSEMBLE APPROACH
WITH THE SFC-700 MB LOW TRACKS AND QPF...WHICH WOULD BASED ON THAT
TRACK AND ASSCD FVRBL REGION OF MAX UPPER LEVEL DIFFLUENCE/MID
LEVEL DEFORMATION AND TROWAL...
WOULD FAVOR A POTENTIAL FOR HEAVY SNOW ACROSS PTNS OF THE LWR MS
VLY TO INCLUDE CEN AR NEWRD THROUGH SERN MO/WRN KY.
OBVIOUSLY...GIVEN THE GUIDANCE SPREAD AT THIS POINT...FCST
CONFIDENCE IS AVG AT BEST (AVG FOR A DAY 3 FCST). THROW IN THE
ANOMALOUS NATURE OF THIS EVENT (500 MB HEIGHTS ~ 2 STD DEVS BELOW
NORMAL FOR THE LOWER MS VLY)...AS WELL AS THE POTENTIAL FOR SHIFTS
IN THE STORM TRACK...DRY SLOT...AND CONVECTIVELY ENHANCED REGIONS
(OR ALL OF THE ABOVE)...HPC PROBABILITIES WHERE MOST HEAVILY
WEIGHTED TOWARD THE LOWER THRESHOLDS (I.E. >4 INCHES) AT THIS
POINT. FOR NOW...THE DAY 3 FINAL PROBS DID INCLUDE A STRIPE OF 10%
OF >8 INCHES OVER PTNS OF CEN AND NERN ARK...AGAIN TAKING THE
ENSEMBLE APPROACH WITH THE STORM TRACK (EVEN THOUGH THE
ECMWF/UKMET WERE ABOUT 6 HRS SLOWER).

THE DEEPENING NATURE OF THIS SYSTEM (700-500 MB LOWS) AS THE
TROUGH AXIS BECOMES MORE NEGATIVELY TILTED WILL ALLOW FOR MATURING
CYCLOGENESIS WITH THE GOMEX WIDE OPEN AND COMMA-HEAD STRUCTURES
(CCB...MID-LEVEL TROWAL...AND DRY SLOT) COMING INTO PLAY. ALL THE
MODELS SHOW A GOOD POTENTIAL FOR CONVECTION AS WELL...ANY OF WHICH
IN THE WARM SECTOR COULD CERTAINLY DISRUPT THE MSTR TRANSPORT N-NW
OF THE LOW. HOWEVER AT THE SAME TIME...NEG 850-500 MB THETA-E
LAPSE RATES AND ARE PROGGED TO NUDGE UP INTO CEN-NRN AR INTO FAR
SW TN...WITH WEAK STATIC STABILITY JUST TO THE NORTH. THUS THE
CONCEPTUAL MODEL WOULD SUGGEST THE POTENTIAL FOR ELEVATED
CONVECTION (WHETHER UPRIGHT OR SLANTWISE) AND THUS ENHANCED
SNOWFALL RATES. AGAIN...QUITE A FEW VARYING FACTORS TO CONSIDER
WITH THIS SYSTEM...THUS EXPECT FURTHER ALTERATIONS TO THESE
PROBABILITIES AS THE EVENT DRAWS NEAR.

HURLEY



POST-CHRISTMAS SNOW FOR DALLAS AND ARKLATEX - Joe-Nathan - 12-23-2012 04:32 PM

SHREVEPORT NWS:

[Image: image_full9.jpg]


POST-CHRISTMAS SNOW FOR DALLAS AND ARKLATEX - Joe-Nathan - 12-23-2012 04:44 PM

THE POSTION OF THE LOW WILL BE KEY IN WHO AND HOW MUCH SNOW FOLKS GET CHRISTMAS DAY:

[Image: lowtrack_ensembles.gif]