US HAZARDS ASSESSMENT
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300
PM EST NOVEMBER 06 2009
SYNOPSIS: THE ASSESSMENT PERIOD IS
EXPECTED TO FEATURE ACTIVE WEATHER ACROSS THE GULF COAST, SOUTHEAST, PACIFIC
NORTHWEST, AND PORTIONS OF ALASKA. A WEAK LOW-PRESSURE SYSTEM IS EXPECTED TO
TRAVERSE THE NORTHERN TIER OF THE COUNTRY WITH AN ASSOCIATED COLD FRONT MOVING
FROM THE GREAT PLAINS TO THE EASTERN SEABOARD BY THE MIDDLE OF NEXT WEEK. LATE
SEASON INFLUENCES OF A TROPICAL NATURE COULD AFFECT THE SOUTHEAST. ANOTHER,
MORE POTENT LOW-PRESSURE SYSTEM, IS EXPECTED TO MOVE ONSHORE ACROSS THE PACIFIC
NORTHWEST. DURING THE MIDDLE PORTIONS OF THE ASSESSMENT PERIOD, THE PRIMARY
AREA OF UNSETTLED WEATHER IS EXPECTED TO SHIFT TO THE CENTRAL PORTIONS OF THE
COUNTRY, AS A LOW-PRESSURE SYSTEM DEVELOPS EAST OF THE CENTRAL ROCKIES AND
MOVES NORTHEAST ACROSS THE GREAT PLAINS. THE EASTERN THIRD OF THE COUNTRY
SHOULD COME UNDER THE CALMING INFLUENCE OF HIGH PRESSURE. THE FOCUS OF ACTIVE
WEATHER ACROSS ALASKA IS EXPECTED TO SHIFT FROM SOUTHEAST ALAKSA TO WESTERN
ALASKA AND THE ALEUTIANS.
HAZARDS - ONGOING FLOODING FOR
PARTS OF THE CENTRAL AND SOUTHERN MISSISSIPPI VALLEY, AS WELL AS FOR EASTERN
PORTIONS OF TEXAS.
- HEAVY PRECIPITATION FOR THE PACIFIC NORTHWEST, NOV 9.
- PERIODS OF HEAVY PRECIPITATION FOR SOUTHEAST ALASKA, NOV 9-10, 12-13.
- HEAVY PRECIPITATION FOR PORTIONS OF THE SOUTHEAST, NOV 9-12.
- HEAVY PRECIPITATION FOR WESTERN ALASKA, NOV 11-12.
- SEVERE DROUGHT CONTINUES IN PARTS OF WISCONSIN, TEXAS, ARIZONA, NEW MEXICO,
CALIFORNIA, NEVADA, AND WASHINGTON. SOME RELIEF IS EXPECTED ACROSS WISCONSIN,
WASHINGTON, NORTHERN CALIFORNIA, AND SOUTH CAROLINA.
DETAILED
SUMMARYFOR MONDAY NOVEMBER 09 - WEDNESDAY
NOVEMBER 11: A RIDGE OF HIGH PRESSURE IS FORECAST ALONG THE EAST COAST. ON
THE SOUTHERN FLANK OF THIS RIDGE, STRONG EASTERLIES ACROSS MOST OF THE EAST
COAST OF FLORIDA AND PORTIONS OF GEORGIA ARE EXPECTED TO PERSIST THROUGH
MONDAY, NOVEMBER 9. WINDS RANGING FROM 20-30 MPH ARE POSSIBLE, WITH THE HIGHEST
WINDS FURTHER SOUTH. THIS TYPE OF WEATHER PATTERN IS ALSO ASSOCIATED WITH
DANGEROUS RIP CURRENTS, MINOR COASTAL EROSION, AND RED FLAG WARNINGS ACROSS
FLORIDA. CONCERNED PARTIES SHOULD CONTACT THE LOCAL WEATHER FORECAST OFFICE FOR
MORE INFORMATION.
A SURGE OF TROPICAL MOISTURE, INTERACTING WITH THE COLD FRONT THAT IS
EXPECTED TO MOVE INTO THE SOUTHEAST, SHOULD PROVIDE SIGNIFICANT RAINFALL TO
PORTIONS OF THE SOUTHEAST. ADDITIONALLY, MOISTURE ASSOCIATED WITH TROPICAL
STORM IDA SHOULD PROVIDE A SECOND MOISTURE SURGE. CONSULT FORECAST PRODUCTS
FROM THE NATIONAL HURRICANE CENTER (WWW.NHC.NOAA.GOV) FOR MORE INFORMATION ON
THE TRACK AND INTENSITY OF TROPICAL STORM IDA.
HIGH PRESSURE TO THE NORTH SHOULD LIMIT THE NORTHWARD PROGRESSION OF THE
MOISTURE ACROSS THE SOUTHEAST, POTENTIALLY CAUSING FLOODING RAINS ACROSS
ALABAMA, GEORGIA, AND FLORIDA. CONTACT YOUR LOCAL WEATHER FORECAST OFFICE AND
HEED WARNINGS FROM LOCAL AUTHORITIES.
FURTHER NORTH, ON THE EASTERN FLANK OF THE HIGH PRESSURE THAT IS FORECAST
TO BUILD IN BEHIND THE COLD FRONT, WINDY CONDITIONS ARE LIKELY ACROSS THE
NORTHEAST WEDNESDAY NOVEMBER 11.
ACROSS THE PACIFIC NORTHWEST, A POTENT LOW-PRESSURE SYSTEM IS FORECAST TO
MOVE ONSHORE IN BRITISH COLUMBIA DURING THE DAY ON NOVEMBER 9. RAINFALL
AMOUNTS COULD EXCEED 3 INCHES ACROSS SOME PARTS OF WASHINGTON AND OREGON,
BEFORE THE RAINS ABATE DURING THE DAY ON NOVEMBER 10.
MULTIPLE STORM SYSTEMS ARE FORECAST TO IMPACT ALASKA WITH A STRONG COLD
FRONT FORECAST TO MOVE ACROSS WESTERN ALASKA AND THE ALEUTIANS NOVEMBER 10.
BEHIND THAT COLD FRONT, WIND SPEEDS BETWEEN 30 AND 40 MPH ARE POSSIBLE IN
ISOLATED PLACES, WITH MOST WIND SPEEDS NOT MEETING HAZARD CRITERIA. A SECOND
LOW-PRESSURE SYSTEM IS FORECAST TO DEVELOP ON THE WESTERN END OF THAT COLD
FRONT, BRINGING SIGNIFICANT PRECIPITATION AND BLOWING SNOW ACROSS WESTERN
ALASKA THROUGH NOVEMBER 12.
FOR THURSDAY NOVEMBER 12 - MONDAY
NOVEMBER 16: A SHORTWAVE IS FORECAST TO MOVE SOUTHWARD ALONG THE PACIFIC
COAST DURING THE MIDDLE OF NEXT WEEK. UNCERTAINTY ABOUT THE STRENGTH OF
SURFACE REFLECTION OF THAT SHORTWAVE IS HIGH, AS THE 12Z ECMWF SOLUTION DEPICTS
A 1006MB LOW JUST WEST OF PUGET SOUND WHILE THE 12Z GFS SOLUTION DEPICTS
RIDGING, AND A MUCH WEAKER SHORTWAVE. PRECIPITATION AMOUNTS INDICATED IN THE
MODEL SOLUTIONS VARY GREATLY AS A RESULT OF THE VARIANCE IN STRUCTURE,
THEREFORE NO HAZARD IS DEPICTED DUE TO HIGH UNCERTAINTY IN THE TIMING OF THE
FEATURES.
BOTH MODELS DO COME INTO BETTER AGREEMENT ON THE DEVELOPMENT OF A
LOW-PRESSURE SYSTEM ACROSS THE CENTRAL ROCKIES DURING THE MIDDLE OF NEXT WEEK.
BOTH MODELS INDICATE THAT THE LOW-PRESSURE SYSTEM SHOULD MOVE INTO THE CENTRAL
GREAT PLAINS, BUT VARY WIDELY ON THE AMOUNT OF PRECIPITATION. GIVEN THE
LOCATION OF THE LOW-PRESSURE SYSTEM AND WIND DIRECTION, SIGNIFICANT OROGRAPHIC
ENHANCEMENT OF PRECIPITATION IS LIKELY ACROSS WYOMING , IDAHO AND NORTHERN
COLORADO, BUT A BROADER HAZARD CANNOT BE DEPICTED DUE TO UNCERTAINTY IN THE
FORECAST.
THE SECOND LOW-PRESSURE SYSTEM MOVING ACROSS ALASKA IS EXPECTED TO MOVE
INTO THE GULF OF ALASKA LATE NEXT WEEK, AND SHOULD BRING ANOTHER ROUND OF HEAVY
PRECIPITATION TO SOUTHEAST ALASKA AND THE ALASKAN PANHANDLE.
FOR TUESDAY
NOVEMBER 17 - FRIDAY NOVEMBER 20: A STRONG TROUGH IS FORECAST TO EXTEND
FROM CENTRAL ALASKA TO THE EASTERN PACIFIC WITH RIDGING PRESENT FROM THE FOUR
CORNERS REGION TO THE GREAT LAKES. THIS PATTERN IS EXPECTED TO SUPPORT WET
CONDITIONS ACROSS SOUTHEASTERN ALASKA, THE WEST COAST AND FROM THE SOUTHERN
PLAINS TO THE MID-ATLANTIC. WARMER THAN AVERAGE CONDITIONS ARE EXPECTED ACROSS
THE NORTHERN TIER OF THE COUNTRY.
SEVERE DROUGHT IS EXPECTED TO PERSIST ACROSS CALIFORNIA, NEVADA, ARIZONA,
AND NEW MEXICO. SOME DROUGHT RELIEF IS EXPECTED ACROSS WISCONSIN, TEXAS,
NORTHERN CALIFORNIA, AND SOUTH CAROLINA.
FORECASTER: MATT
ROSENCRANS
$$