Prognostic Meteorological Discussion
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000
FXUS01 KWBC 210829
PMDSPD

SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
429 AM EDT MON APR 21 2014

VALID 12Z MON APR 21 2014 - 12Z WED APR 23 2014

...SEVERE WEATHER WILL BE POSSIBLE TODAY FROM CENTRAL TO NORTHEAST
TEXAS...

...HEAVY SNOW IS EXPECTED ACROSS THE OREGON CASCADES AND OVER THE
TETONS...


A DEFINITIVE PATTERN CHANGE WILL BE UNDERWAY AS A STRONG UPPER
TROF SETS UP ACROSS THE WESTERN U.S. BY TUESDAY. THIS WILL LEAD TO
QUITE A SINUSOIDAL PATTERN WITH UNSETTLED WEATHER ACROSS THE
WESTERN/EASTERN U.S. WHILE RIDGING ACROSS THE MIDDLE OF THE NATION
KEEPS CONDITIONS MORE TRANQUIL.

TO BEGIN THE FORECAST PERIOD, A SLOW MOVING COLD FRONT WAS SEEN
MOVING TOWARD THE MIDDLE MISSISSIPPI VALLEY AND CENTRAL PLAINS.
MID-LEVEL ENERGY ASSOCIATED WITH A WEAKENING TROF SHOULD HELP
IGNITE SHOWERS AND THUNDERSTORMS AHEAD OF THE ADVANCING COLD
FRONT. MUCH OF THE CONVECTION SHOULD SPAWN ALONG A NORTH-SOUTH
ORIENTED TROF ACROSS TEXAS/OKLAHOMA WHERE LOW-LEVEL CONVERGENCE
WILL BE MAXIMIZED. SUFFICIENT DAYTIME HEATING IS EXPECTED LEADING
TO LARGE AMOUNTS OF INSTABILITY IN THE ATMOSPHERE. THE STORM
PREDICTION CENTER OUTLOOK SUGGESTS A THREAT FOR SEVERE
THUNDERSTORM DEVELOPMENT ANYWHERE FROM CENTRAL TEXAS TOWARD THE
ARKANSAS/LOUISIANA BORDER THROUGH TONIGHT.

AS AN UPPER TROF IN THE NORTHERN STREAM BEGINS TO DIG THROUGH THE
UPPER GREAT LAKES EARLY TUESDAY, THE COLD FRONT IS FORECAST TO
ACCELERATE REACHING THE EASTERN SEABOARD BY LATE TUESDAY NIGHT.
SHOWERS AND THUNDERSTORMS WILL BREAK OUT ALONG AND AHEAD OF THE
BOUNDARY WITH ANY WINTRY PRECIPITATION REMAINING NORTH OF THE
U.S./CANADIAN BORDER. AHEAD OF THIS ADVANCING COLD FRONT THE
TEMPERATURES SHOULD BE QUITE MILD WITH HIGHS WELL INTO THE 70S
ALONG THE I-95 CORRIDOR ON TUESDAY.

THE CHANGE IN THE PATTERN BRINGING THE LARGE UPPER TROF TO THE
WEST WILL ALLOW COOLER AND WETTER CONDITIONS TO AFFECT THE REGION.
THE COMBINATION OF ONSHORE FLOW WITH FRONTAL AND OROGRAPHIC LIFT
WILL HELP SPREAD AN EXPANSIVE REGION OF PRECIPITATION TO THE
WESTERN U.S. SNOW LEVELS SHOULD FALL SUFFICIENTLY TO BRING DECENT
ACCUMULATIONS TO THE OREGON CASCADES AND ACROSS THE TETONS. BOTH
OF THESE MOUNTAIN RANGES CAN EXPECT SNOW TOTALS THROUGH EARLY
WEDNESDAY OF 6 TO 10 INCHES WHILE LOCALIZED HEAVIER AMOUNTS WILL
BE POSSIBLE. THE OTHER ASPECT OF THIS SYSTEM WILL BE DRY AND GUSTY
WINDS EXPECTED AS THE PRESSURE GRADIENT TIGHTENS ACROSS THE
INTERMOUNTAIN WEST. AN ENHANCED RISK FOR WILDFIRE DEVELOPMENT IS
IN PLACE FOR THE DESERT SOUTHWEST ON TUESDAY WITH LOCATIONS
FURTHER EAST BEING AFFECTED BY MID-WEEK.


RUBIN-OSTER


GRAPHICS AVAILABLE AT WWW.WPC.NCEP.NOAA.GOV
$$




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