Prognostic Meteorological Discussion
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398
FXUS02 KWBC 261546
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1046 AM EST SUN FEB 26 2017

VALID 12Z WED MAR 01 2017 - 12Z SUN MAR 05 2017

...OVERVIEW AND GUIDANCE PREFERENCES...

AN UPPER TROUGH IS EXPECTED TO PROGRESS FROM THE CENTRAL TO
EASTERN U.S. LATER THIS WEEK, WHILE THE ASSOCIATED COLD FRONT
PRESSES TOWARDS THE APPALACHIANS ON WEDNESDAY AND THEN OFF THE
EASTERN SEABOARD BY THURSDAY.  BEHIND THIS SYSTEM, AN IMPULSE OF
SHORTWAVE ENERGY DROPPING INTO THE NORTH CENTRAL U.S. ON THURSDAY
COULD RESULT IN A WEAK WAVE OF LOW PRESSURE STREAKING FROM THE
UPPER MIDWEST TO THE NORTHERN MID-ATLANTIC STATES LATE THIS WEEK,
BUT THEN FLOW IS EXPECTED TO BECOME QUITE ZONAL ACROSS THE
NORTHERN HALF OF THE NATION BY NEXT WEEKEND.  MEANWHILE, A
SLOW-MOVING SHORTWAVE IN THE SOUTHERN STREAM WILL GRADUALLY EDGE
FROM THE SOUTHWEST/NORTHERN MEXICO ON FRIDAY TO THE SOUTHERN
PLAINS ON SUNDAY.

THE WPC DAY 3-7 FORECAST STARTED WITH A BLEND OF FAIRLY AGREEABLE
GUIDANCE, WHICH INCLUDED THE GFS, GEFS MEAN, ECMWF, ECMWF ENSEMBLE
MEAN, AND CONTINUITY.  HOWEVER, SLIGHTLY LESS WEIGHT WAS GIVEN THE
GFS SINCE IT WAS A TAD FASTER THAN MODEL CONSENSUS WITH THE TIMING
OF THE COLD FRONT PUSHING OFF THE ATLANTIC COAST, AND IT WAS ON
THE MUCH DEEPER AND NORTHWEST SIDE OF MODEL SPREAD WITH THE DEPTH
AND TRACK OF A SURFACE LOW EXPECTED TO STRENGTHENING ALONG THE
BOUNDARY AND LIFT NORTHEASTWARD OUT OF THE GREAT LAKES REGION.
THE GFS ALSO CONTINUED TO ADVERTISE ONE OF THE STRONGEST SOLUTIONS
WITH THE SHORTWAVE ENERGY POSSIBLY DROPPING INTO THE NORTH CENTRAL
U.S. ON THURSDAY.  ELSEWHERE, ENSEMBLE MEMBERS ARE STILL SHOWING A
LARGE AMOUNT OF SPREAD WITH FLOW SETTING UP OVER THE NORTHWEST
LATE THIS WEEK AND INTO NEXT WEEKEND, SUGGESTING THERE REMAINS
SOME UNCERTAINTY IN THE DETAILS OF THE FORECAST.


...WEATHER HIGHLIGHTS/THREATS...

THE INITIAL FOCUS OF THE FORECAST WILL BE WITH HEAVY RAIN AND
STRONG CONVECTION DEVELOPING AHEAD OF THE COLD FRONT PRESSING
THROUGH THE EASTERN THIRD OF THE NATION WEDNESDAY INTO THURSDAY,
WHERE THE STORM PREDICTION CENTER HAS ALREADY HIGHLIGHTED THE
POTENTIAL FOR SEVERE STORMS (PLEASE REFER TO WWW.SPC.NCEP.NOAA.GOV
FOR MORE DETAILS).  SNOW AND STRONG WINDS WILL BE POSSIBLE TO THE
NORTHWEST OF A SURFACE LOW RAPIDLY DEEPENING ALONG THE BOUNDARY
WHICH, DEPENDING ON THE EXACT TRACK, COULD IMPACT PORTIONS OF THE
UPPER MISSISSIPPI VALLEY/UPPER GREAT LAKES AND MAYBE EVEN INTERIOR
NEW ENGLAND.  ALSO, TEMPERATURES COULD APPROACH OR EXCEED RECORD
HIGHS AHEAD OF THE FRONT, BUT THEN TEMPERATURES SHOULD RETURN TO
NEAR NORMAL IN THE SYSTEM`S WAKE.

OUT WEST, STRONG AND MOIST WESTERLY/SOUTHWESTERLY FLOW SETTING UP
OVER THE NORTHWESTERN U.S. LATER THIS WEEK SHOULD BRING PERIODS OF
HEAVY RAIN AND MOUNTAIN SNOW TO THE WINDWARD TERRAIN OF THE
PACIFIC NORTHWEST AND NORTHERN ROCKIES, WHILE ACROSS THE SOUTHERN
TIER, A RETREATING WARM FRONT COMBINED WITH RETURN FLOW OUT OF THE
GULF OF MEXICO COULD BRING MODERATE TO HEAVY RAIN INTO SOUTH TEXAS
BY NEXT WEEKEND.


GERHARDT


$$





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