Prognostic Meteorological Discussion
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FXUS02 KWBC 100610
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
110 AM EST WED FEB 10 2016

VALID 12Z SAT FEB 13 2016 - 12Z WED FEB 17 2016

...RECORD COLD FOR PORTIONS OF THE NORTHEAST THIS WEEKEND...

...POTENT WINTER STORM POSSIBLE NEXT TUE-WED IN THE EAST...

...OVERVIEW...

DEEP TROUGHING IN THE EAST THIS WEEKEND WILL GIVE WAY TO A PERHAPS
POTENT SOUTHERN STREAM SHORTWAVE TUE-WED WHILE THE WEST WILL SEE
RISING THEN FALLING HEIGHTS. WHAT STARTS OUT AS A RATHER DRY AND
COLD WEEKEND IN THE EAST WILL TRANSITION TO LESS COLD EARLY NEXT
WEEK AS A DEVELOPING SYSTEM MOVES ALONG THE GULF COAST AND
SOUTHEAST. THIS IS FORECAST TO TURN UP THE COAST TUE/WED WITH SOME
WINTRY CONSEQUENCES. PRECIPITATION IN THE WEST WILL BE CONFINED TO
THE NORTHWEST -- WA/OR/ID/MT -- AS CALIFORNIA REMAINS UNDER THE
CONTROL OF AN UPPER HIGH SLIDING SOUTHEASTWARD INTO OLD MEXICO
NEXT WEEK.


...GUIDANCE ASSESSMENT...

THE GFS REMAINS SLOWER THAN THE ECMWF/ECENS MEAN WITH THE INCOMING
SHORTWAVE INTO WA/OR ON SATURDAY... AS HAS BEEN THE CASE FOR A FEW
DAYS. THE GFS HAS BEEN MOST INCONSISTENT WITH THIS FEATURE WHILE
THE ECMWF/CMC AND THE ECMWF EPS SEEM TO HAVE A BETTER HANDLE ON
IT. USED THAT CLUSTER THROUGH MUCH OF THE FORECAST. IN THE EAST,
THE ECMWF AND ITS ENSEMBLES WERE STILL A BIT DEEPER WITH THE
TROUGH THAN THE GFS/GEFS THIS WEEKEND... AGAIN, AS HAS BEEN THE
CASE.

BY SUN/MON, THE DIFFERENCES AMONG THE MODELS MANIFEST MORE AT THE
SURFACE AS LOW PRESSURE STARTS TO ORGANIZE OVER TEXAS AND THE
LOWER MS VALLEY. STILL FAVORED THE ECMWF/CMC-LED CLUSTER AS THE
GFS EMPHASIZED THE NORTHERN STREAM ENERGY MORE SO THAN THE
SOUTHERN... WHICH IS WHAT THE ECMWF SHOWED A FEW DAYS AGO BUT HAS
SINCE ADJUSTED. EITHER WAY, BY TUESDAY ALL MODELS SHOW LOW
PRESSURE DEEPENING NEAR OR OFF THE SOUTHEAST COAST AND TURNING
NORTHEASTWARD. GFS RUNS HAVE BEEN TO THE EAST/OFFSHORE WHILE THE
ECMWF AND ITS MEAN HAVE RECENTLY SHOWN AN INLAND RUNNER ALONG
I-95/91 INTO NEW ENGLAND. THE CANADIAN LIED JUST TO THE EAST OF
THE ECMWF NEAR THE GEFS MEAN. OPTED TO TREND TOWARD A
MULTI-MODEL/ENSEMBLE BLEND BY TUES EVENING WHICH INCLUDED THE 18Z
GEFS MEAN. LOTS OF DETAILS TO SORT OUT BUT THE SIGNAL/AGREEMENT IN
THE ENSEMBLE MEANS IS SIGNIFICANT.

BACK TO THE WEST BY NEXT WEDNESDAY AND THERE REMAINS A LARGE
AMOUNT OF SPREAD WITH THE DEPTH/SPEED OF THE NEXT TROUGH TO MOVE
TOWARD THE PAC NW. GEFS MEMBERS WERE MOSTLY SLOWER THAN THE ECMWF
ENSEMBLES BUT SOMETHING IN BETWEEN SHOULD SUFFICE GIVEN THE LACK
OF CONTINUITY.


...SENSIBLE WEATHER HIGHLIGHTS...

VERY COLD IN THE EAST THIS WEEKEND -- MANY RECORD LOW MINS AND LOW
MAXES -- AS THE CANADIAN ARCTIC AIRMASS DROPS RIGHT THROUGH THE
NORTHEAST. SOUTHWESTERN STATES WILL BE NEARLY THE OPPOSITE WITH
RECORD HIGH MAX/MIN TEMPERATURES PROBABLE IN CA/AZ INTO THE
PACIFIC NORTHWEST. TEMPERATURES IN THE CENTRAL STATES WILL TREND
WARMER FROM WEST TO EAST.

PRECIPITATION IN THE WEST WILL COME IN WAVES AS SUCCESSIVE
SHORTWAVES AND SURFACE BOUNDARIES MOVE INLAND. THIS SHOULD FAVOR
THE COASTAL RANGE AND CASCADES MOST AND THEN ALSO INTO THE
BITTERROOTS. NORTHERN PLAINS SHOULD SEE MOSTLY LIGHT QPF AS
NORTHERN STREAM ENERGY MOVES THROUGH... THOUGH SOME
MODELS/ENSEMBLES SHOW ABOUT A HALF INCH OVER 24-48 HRS.

THE EAST WILL BECOME INCREASINGLY COMPLICATED IN BOTH PRECIP TYPE,
TIMING, AND AMOUNT AS THE COASTAL SYSTEM DEVELOPS. ANTECEDENT COLD
AIRMASS WILL LIKELY MEAN A PERIOD OF WINTRY WEATHER IN THE
SOUTHERN APPALACHIANS AND INTERIOR SOUTHEAST WITH ICING A VERY
REAL THREAT AS THE WARM AIR OVERRIDES THE IN SITU COLD AIRMASS.
STORM TRACK WILL ULTIMATELY DETERMINE SPECIFICS. QPF FROM THE
SYSTEM PER THE ENSEMBLES IS ALREADY ON THE MODERATE/HIGH SIDE
INDICATING THAT SOME LOCATIONS WILL SEE QUITE A BIT OF
PRECIPITATION -- PROBABLY OF ALL TYPES.


FRACASSO

$$





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