Prognostic Meteorological Discussion
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000
FXUS01 KWBC 212019
PMDSPD

SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
318 PM EST SUN DEC 21 2014

VALID 00Z MON DEC 22 2014 - 00Z WED DEC 24 2014

...A WINTER STORM SHOULD AFFECT THE NORTHERN PLAINS/UPPER MIDWEST
REGION...

...HEAVY RAINFALL EXPECTED ALONG THE OLYMPICS AND CASCADES...

...SEVERE WEATHER POSSIBLE ON TUESDAY ALONG THE CENTRAL/EASTERN
GULF COAST...


THE UPPER PATTERN ENTERING NEXT WEEK WILL BECOME OF HIGHER
AMPLITUDE WITH A STRONG TROUGH DIGGING INTO THE CENTER OF THE
COUNTRY. INITIAL IMPULSES CURRENTLY RACING ACROSS THE UPPER
INTERMOUNTAIN WEST WILL HELP CARVE OUT A PRONOUNCED CLOSED LOW
ACROSS THE MIDDLE MISSISSIPPI VALLEY BY MONDAY EVENING. THIS WILL
BE THE FOCUS FOR UNSETTLED WEATHER OVER THE NORTHERN PLAINS AND
UPPER MIDWEST WHERE WINTRY PRECIPITATION IS EXPECTED. THE SYSTEM
AT HAND IS NOT FORECAST TO GET THE BEST MOISTURE SUPPORT GIVEN A
BOUNDARY ALONG THE GULF COAST WILL ROB SOME OF THE INCOMING
MOISTURE TRANSPORT. HOWEVER, THE UPPER SYSTEM IS EXPECTED TO BE
SLOW MOVING WHICH SHOULD ALLOW A LONGER TIME FOR SNOWFALL
ACCUMULATIONS. THE WPC WINTER WEATHER GRAPHICS SUGGEST A
WIDESPREAD AXIS OF 4 TO 6 INCHES OF SNOW ANYWHERE FROM SOUTH
DAKOTA EASTWARD INTO MINNESOTA AND NORTHERN WISCONSIN/UPPER
PENINSULA OF MICHIGAN.

HEAVY PRECIPITATION ALONG THE WEST COAST WILL PERSIST WITH A FOCUS
ALONG THE COASTAL RANGES AND WASHINGTON/OREGON CASCADES. STRONG
ONSHORE FLOW WILL TRANSPORT ANOMALOUS MOISTURE INLAND WITH HEAVY
RAINFALL AFFECTING THE WINDWARD SLOPES OF THE LOCAL TOPOGRAPHY.
WHILE NOT NEARLY AS IMPRESSIVE AS RECENT DAYS, THE FORECAST
SUGGESTS ANOTHER 1 TO 3 INCHES OF RAINFALL ACROSS THE REGION.
LOOKING FARTHER INLAND, MODERATE TO HEAVY SNOW IS LIKELY OVER THE
WASATCH AND COLORADO ROCKIES WITH 1 TO 2 FOOT AMOUNTS POSSIBLE
THROUGH MONDAY. THIS IS IN RESPONSE TO STRONG LIFT WITH THE
MID-LEVEL ENERGY PASSING OVERHEAD IN CONJUNCTION WITH ENHANCED
VERTICAL MOTIONS ALONG THE SURGING COLD FRONT.

GIVEN THE STRONG UPPER TROUGH ANCHORING THE CENTER OF THE COUNTRY,
A WELL DEFINED COLD FRONT WILL ADVANCE EASTWARD IN TIME WITH
CONVECTION BREAKING OUT ALONG AND AHEAD OF IT. SOME OF THE
THUNDERSTORMS MAY BECOME SEVERE ALONG THE CENTRAL/EASTERN GULF
COASTS ON TUESDAY BASED ON THE LATEST STORM PREDICTION CENTER
OUTLOOK.

A WET PERIOD IS BEING FORECAST FROM THE SOUTHEASTERN STATES UP
ALONG THE I-95 CORRIDOR. A STALLED FRONTAL BOUNDARY HAS CONTINUED
TO DRIVE ACTIVE CONVECTION ACROSS THE SOUTHEASTERN U.S. GRADUALLY
A WAVE OF LOW PRESSURE WILL LIFT ALONG THE EAST COAST WHICH WILL
HELP CARRY LIGHT TO MODERATE RAINFALL TOWARD THE MID-ATLANTIC
REGION. LOCATIONS ON THE FAR WESTERN END OF THE PRECIPITATION
SHIELD MAY SEE PERIODS OF FREEZING RAIN GIVEN FAVORABLE
THERMODYNAMIC PROFILES. THIS IS PRIMARILY THE CASE OVER THE
CENTRAL APPALACHIANS WHERE BOUNDARY LAYER TEMPERATURES WILL REMAIN
BELOW FREEZING.


RUBIN-OSTER

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





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