Prognostic Meteorological Discussion
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FXUS02 KWBC 291621
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1220 PM EDT MON AUG 29 2016

VALID 12Z THU SEP 01 2016 - 12Z MON SEP 05 2016

...PATTERN OVERVIEW...

AN UPPER TROF AMPLIFYING ALONG THE WEST COAST LATER THIS WEEK
SHOULD BEGIN TO PROGRESS INLAND AND EXPAND OVER THE WESTERN HALF
OF THE NATION BY EARLY NEXT WEEK.  DOWNSTREAM...AN UPPER RIDGE
CENTERED OVER THE NORTH CENTRAL U.S. ON THURSDAY SHOULD GRADUALLY
SHIFT EASTWARD AND EVENTUALLY REPLACE A BROAD TROF INITIALLY
CARVED OUT ACROSS THE GREAT LAKES AND NORTHEAST.  ALSO...THE
NATIONAL HURRICANE CENTER ISSUING ADVISORIES ON T.D. EIGHT WHICH
SHOULD BE EXITING AWAY FROM THE EASTERN SEABOARD BY THURSDAY...AND
T.D. NINE WHICH IS EXPECTED TO MOVE TOWARDS THE CENTRAL GULF OF
MEXICO BEFORE RECURVING AND TRACKING TOWARDS THE BIG BEND OF
FLORIDA LATER THIS WEEK (PLEASE REFER TO WWW.NHC.NOAA.GOV FOR THE
LATEST INFORMATION).


...GUIDANCE/UNCERTAINTY ASSESSMENT...

MODEL GUIDANCE IS IN VERY GOOD AGREEMENT WITH THE LARGE SCALE
EVOLUTION OF FLOW OVER THE LOWER 48 LATER THIS WEEK AND THROUGH
THE WEEKEND.  THE WPC DAY 3-7 FORECAST STARTED WITH A GENERAL
CONSENSUS BLEND TO SMOOTH OUT SOME OF THE TIMING/AMPLITUDE
DIFFERENCES THAT DEVELOP WITH SHORTWAVE ENERGY EMBEDDED IN THE
WESTERN U.S. TROF...WHICH IS EXPECTED TO LIFT OUT OF THE
NORTHWEST/NORTHERN ROCKIES ON FRIDAY.  ALSO...A CONSENSUS BLEND
WORKED WELL WITH THE GROWING MODEL SPREAD THAT DEVELOPS WITH THE
TIMING AND STRENGTH OF T.D. NINE POTENTIALLY LIFTING AWAY FROM THE
CAROLINA COAST THIS WEEKEND.


...WEATHER HIGHLIGHTS/THREATS...

PERIODS OF HEAVY RAINS AND STRONG WINDS WILL BE POSSIBLE WITH T.D.
NINE TRACKING TOWARDS THE BIG BEND OF FLORIDA LATER THIS
WEEK...AND LOCATIONS ACROSS THE SOUTHEAST SHOULD CONTINUE TO
MONITOR THE FORECAST FROM THE NATIONAL HURRICANE CENTER CLOSELY.
A GENERAL COOLING TREND IS EXPECTED BENEATH THE UPPER TROUGH
MOVING INLAND OVER THE WESTERN U.S....WITH TERRAIN ENHANCED
PRECIPITATION POSSIBLE OVER THE PACIFIC NORTHWEST AND NORTHERN
ROCKIES ON FRIDAY.  AT THE LEADING EDGE OF HEIGHT FALLS
PROGRESSING THROUGH THE WESTERN U.S....A COLD FRONT PUSHING OUT
ACROSS THE NORTH CENTRAL U.S. SHOULD PROVIDE RELIEF FROM THE WELL
ABOVE NORMAL TEMPERATURES...BUT THEN THE BOUNDARY COULD SERVE AS A
FOCUS FOR HEAVY RAIN AND THUNDERSTORMS AS IT SLOWS DOWN WHILE
TRYING TO PRESS THROUGH THE UPPER/MIDDLE MISSISSIPPI VALLEY THIS
WEEKEND.  FINALLY...SURFACE HIGH PRESSURE BUILDING INTO THE EAST
WILL BRING A COUPLE DAYS OF NEAR/SLIGHTLY BELOW NORMAL
TEMPERATURES LATE THIS WEEK...BUT THEN THE WARMING TREND THAT
FOLLOWS WITH THE APPROACHING UPPER RIDGE MAY BRING ANOMALIES BACK
UP TO AT LEAST PLUS 5-10F FROM THE OHIO VALLEY TO THE NORTHEAST BY
EARLY NEXT WEEK.


GERHARDT

$$





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