023
FXUS01 KWBC 220757
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
357 AM EDT MON SEP 22 2008
VALID 12Z MON SEP 22 2008 - 00Z WED SEP 24 2008
CURRENTLY THERE IS A COLD FRONT OVER THE MID-ATLANTIC REGION THAT
EXTENDS WESTWARD INTO THE OHIO VALLEY...LITTLE PRECIPITATION IS
ASSOCIATED WITH THIS BOUNDARY. THIS FRONTAL ZONE WILL TRANSITION
INTO A STATIONARY BOUNDARY AND THEN SLOWLY DISSIPATE OVER THE NEXT
24HRS.
ADDITIONALLY...THERE IS A SYSTEM OVER THE CENTRAL ROCKIES AND
NORTHERN PLAINS THAT WILL PERSIST THROUGHOUT THIS FORECAST PERIOD
AND BE THE PRIMARY WEATHER PRODUCER ON MONDAY AND TUESDAY. THIS
SYSTEM HAS ALREADY BROUGHT THUNDERSTORMS AND GOOD-SIZED HAIL TO
PARTS OF NEBRASKA AND THE DAKOTAS...AND IS EXPECTED TO DELIVER
MORE OF THE SAME AS THE COLD FROM PUSHES EASTWARD. THE LONGWAVE
TROUGH THAT IS DRIVING THIS SYSTEM WILL CONTINUE TO AMPLIFY ON
MONDAY. A LOT OF ENERGY EMBEDDED WITHIN THE UPPER LEVEL TROUGH
WILL PROPAGATE ACROSS VARIOUS PARTS OF THE NORTHWESTERN U.S. AND
NORTHERN PLAINS...IMPACTING THE EVOLUTION OF THE NORTHERN
PLAINS/CANADIAN PRAIRIE SYSTEM.
AS THE PERIOD BEGINS...THE CORE OF THE PACIFIC JET IS MOVING
ACROSS WYOMING AND MOVING NORTHEASTWARD INTO MONTANA AND NORTH
DAKOTA...ALL THE WHILE...SUSTAINING UPPER LEVEL DIFFLUENCE AND
CONVECTION ITSELF. THE JET CORE WILL ACTUALLY INTENSIFY AS IT
MOVES INTO CANADA...BRINGING THE THREAT OF SEVERE WEATHER NORTH OF
THE U.S./CANADIAN BORDER. IN ITS WAKE...ANOTHER JET CORE WILL DIG
ITS WAY DOWN THE SPINE OF THE ROCKY MOUNTAINS AND EMERGE INTO
EASTERN MONTANA AND THE DAKOTAS. AT THE SURFACE...A NEW WAVE WILL
APPEAR ON THE FRONTAL BOUNDARY AND THUNDERSTORM ACTIVITY WILL
REKINDLE. TOWARDS THE END OF THE PERIOD...THE BEST CHANCE FOR
ACCUMULATIONS WILL MATERIALIZE IN THE WARM SECTOR OVER
MINNESOTA...ALTHOUGH A SCATTERED TO BROKEN PRECIPITATION SHIELD
WILL SPAN FROM MANITOBA AND ONTARIO THROUGH KANSAS.
ELSEWHERE...A COASTAL LOW OFF THE SOUTHEASTERN SHORE WILL
STIMULATE ENHANCED ONSHORE FLOW...RESULTING IN SHOWERS FROM
FLORIDA TO THE CAROLINAS. HEADING WEST...PERSISTENT EASTERLY FLOW
OFF THE GULF OF MEXICO HAS ALREADY STEERED A DEEP PLUME OF
TROPICAL MOISTURE INTO TEXAS AND NORTHEASTERN MEXICO. SATELLITE
DATA SHOWS AN AREA OF DISTURBED WEATHER JUST EAST OF MEXICO...AND
THIS COMPLEX WILL CONTINUE TO MOVE WESTWARD...BRINGING
THUNDERSTORMS INTO SOUTHERN TEXAS AND EASTERN MEXICO ON MONDAY AND
TUESDAY. LAST BUT NOT LEAST...A NEW PACIFIC CYCLONE IS ON THE
HORIZON FOR BRITISH COLUMBIA...ALTHOUGH SOME PRECIPITATION WILL
REACH THE OLYMPIC PENINSULA BY TUESDAY EVENING.
SZATANEK
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