US HAZARDS ASSESSMENT
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300
PM EST FEBRUARY 09 2010
SYNOPSIS: EARLY IN THE PERIOD, AN INTENSE
LOW PRESSURE SYSTEM IS FORECAST TO BECOME NEARLY STATIONARY NEAR THE CANADIAN
MARITIMES. COLD HIGH PRESSURE OVER THE CENTRAL STATES IS LIKELY TO RESULT IN A
STRONG PRESSURE GRADIENT ACROSS THE NORTHEAST, LEADING TO BLUSTERY
NORTHWESTERLY WINDS ACROSS THE REGION. WEAK LOW PRESSURE FORECAST TO TRACK
EASTWARD ACROSS THE GULF OF MEXICO MAY BRING A MIX OF WINTRY PRECIPITATION TO
PARTS OF THE DEEP SOUTH. THE WEATHER PATTERN FAVORS THE LIKELIHOOD FOR
CONTINUED VERY COLD AIR OVER THE CENTRAL AND EASTERN PARTS OF THE COUNTRY
THROUGH NEXT WEEK.
HAZARDS - MUCH BELOW NORMAL
TEMPERATURES FOR THE SOUTH, MIDWEST, AND EAST FEB 12-23.
- HEAVY RAIN FOR FLORIDA FEB 12-13.
- LIGHT TO MODERATE SNOW ACROSS PARTS OF THE SOUTH FEB 12.
- ONGOING FLOODING FOR PARTS OF THE SOUTHEAST, NORTHEAST TEXAS, AND
MISSISSIPPI.
- SEVERE DROUGHT IN PARTS OF WISCONSIN, ARIZONA, NEVADA, CALIFORNIA, AND
WASHINGTON.
DETAILED SUMMARYFOR
FRIDAY FEBRUARY 12 - SUNDAY FEBRUARY 14: THE MAJOR LOW PRESSURE SYSTEM THAT
IS EXPECTED TO BRING HEAVY SNOW TO THE NORTHEAST BEFORE THE START OF THE VALID
PERIOD IS FORECAST TO INTENSIFY OFF THE MID-ATLANTIC COAST AND TRACK TO THE
NEWFOUNDLAND AREA BY FRIDAY. LINGERING STRONG WINDS ARE EXPECTED TO AFFECT THE
NORTHEAST INTO FRIDAY, BUT THE POTENTIAL FOR DAMAGING WINDS IS LIKELY TO BE
REDUCED BY THIS TIME. HIGH PRESSURE WILL DOMINATE THE CENTRAL STATES THIS
PERIOD, WITH A REINFORCING SURGE OF COLD HIGH PRESSURE SINKING SOUTHWARD FROM
CANADA. AN UPPER-LEVEL SHORT WAVE MOVING SOUTH AND EAST THROUGH THE GREAT LAKES
REGION IS FORECAST TO BRING A CLIPPER TYPE SYSTEM EASTWARD OVER THE MIDWEST AND
INTO THE NORTHEAST AND MID-ATLANTIC STATES ON SATURDAY-SUNDAY, BRINGING MOSTLY
LIGHT SNOWS ACROSS A BROAD REGION.
MUCH BELOW-NORMAL TEMPERATURES ARE FORECAST TO EXTEND ACROSS MUCH OF THE
CONUS EAST OF THE CONTINENTAL DIVIDE THIS PERIOD.
WEAK LOW PRESSURE IS FORECAST TO TRAVEL EASTWARD ACROSS THE GULF OF MEXICO
ON FRIDAY, BUT MODELS TODAY SUGGEST A MORE SOUTHWARD TRACK THAN INDICATED
YESTERDAY, LOWERING THE CHANCES FOR WIDESPREAD SNOW OR FROZEN PRECIPITATION
ACROSS THE SOUTH. THE ECMWF OPERATIONAL MODEL AND VARIOUS ENSEMBLE MODELS
DEPICT MORE INLAND PRECIPITATION THAN THE RECENT GFS OPERATIONAL RUNS, AND
ENOUGH COLD AIR IS FORECAST TO BE IN PLACE TO RESULT IN SOME FROZEN
PRECIPITATION, MAINLY IN THE FORM OF SNOW. SOME SLEET, RAIN, OR FREEZING RAIN
IS LIKELY TO MIX IN AS WELL. HEAVY RAINS FROM THIS SYSTEM ARE FORECAST ON
FRIDAY-SATURDAY IN FLORIDA.
HEAVY RAIN AND STRONG WINDS FROM AN INTENSE PACIFIC LOW PRESSURE SYSTEM ARE
FORECAST TO STRIKE THE PACIFIC NORTHWEST COAST THIS PERIOD, WITH THE HEAVIEST
RAIN OVER NORTHWEST WASHINGTON. A HAZARD IS NOT POSTED AT THIS TIME AS
PRECIPITATION TOTALS ARE NOT EXPECTED TO BE ESPECIALLY UNUSUAL FOR THIS TIME OF
THE YEAR. STRONG SOUTHWESTERLY WINDS ARE EXPECTED TO ALSO APPROACH HAZARDOUS
CRITERIA ALONG THE COAST OF OREGON AND WASHINGTON.
DEEP LOW PRESSURE IN THE GULF OF ALASKA IS FORECAST TO BRING STRONG WINDS
CLOSE TO THE SOUTHERN COAST OF ALASKA THIS PERIOD, BUT WITH WINDS LIKELY TO BE
NEARLY PARALLEL TO THE COAST, REDUCING THE FETCH OVER THE WATER, A HAZARD FOR
UNUSUALLY HIGH WINDS IS NOT DEPICTED AT THIS TIME.
FOR MONDAY FEBRUARY 15 - FRIDAY
FEBRUARY 19: UPPER-LEVEL TROUGHING OVER THE EASTERN THIRD OF THE NATION
ASSOCIATED WITH A CONTINUED NEGATIVE AO INDEX IS FORECAST TO MAINTAIN
BELOW-NORMAL TEMPERATURES ACROSS MUCH OF THE EASTERN HALF OF THE CONUS. THE
SHORT WAVE TRACKING EASTWARD ACROSS THE GREAT LAKES STATES ALONG WITH THE
CONTINUED UPPER-LEVEL TROUGHING DOMINATING THE EASTERN THIRD OF THE NATION IS
FORECAST TO TRIGGER LAKE-EFFECT AND OROGRAPHIC SNOWS OVER FAVORED AREAS OF THE
APPALACHIANS, MIDWEST, AND NORTHEAST DURING MUCH OF THIS PERIOD.
THE HAZARDS DEPICTION INDICATES A BROAD AREA OF MUCH BELOW-NORMAL
TEMPERATURES FOR THE ENTIRE FORECAST PERIOD, BUT THERE WILL BE FLUCTUATIONS IN
TEMPERATURES FROM DAY TO DAY. ABNORMALLY COLD CONDITIONS WILL NOT AFFECT EVERY
LOCATION EVERY DAY IN THE INDICATED AREA.
HIGH PRESSURE RIDGING OVER THE WEST COAST THIS PERIOD IS LIKELY TO RESULT
IN RELATIVELY DRY AND MILD WEATHER FOR CALIFORNIA AND THE GREAT BASIN, ALTHOUGH
MODELS INDICATE THE POTENTIAL FOR A PACIFIC STORM TO AFFECT CALIFORNIA TOWARD
THE END OF THE PERIOD.
A SERIES OF LOW PRESSURE SYSTEMS ARE FORECAST TO CONTINUE TO AFFECT THE
GULF OF ALASKA REGION, AND LOW PRESSURE DOMINATING THE EASTERN PACIFIC WEST OF
VANCOUVER IS LIKELY TO BRING ADDITIONAL PERIODS OF HEAVY RAIN AND MOUNTAIN
SNOWS TO WESTERN WASHINGTON AND WESTERN OREGON.
FOR SATURDAY FEBRUARY 20 -
TUESDAY FEBRUARY 23: EL NINO CONDITIONS CONTINUE ACROSS THE EQUATORIAL
PACIFIC OCEAN FAVORING ENHANCED TROPICAL RAINFALL NEAR THE DATE LINE AND A
STRONGER AND EASTWARD SHIFTED PACIFIC JET STREAM AND ENHANCED SUBTROPICAL JETS.
THE RECENT LONGER RANGE MODEL GUIDANCE SUPPORTS THIS AND INDICATES A VERY
ACTIVE SOUTHERN JET STREAM ACROSS THE GULF OF MEXICO.
IN ADDITION, CONTINUED EAST COAST TROUGHING WILL LIKELY LEAD TO PERSISTING
BELOW-NORMAL TEMPERATURES FOR MUCH OF THE EASTERN HALF OF THE NATION.
FORECASTER: DOUG LECOMTE
$$