Climate Prediction Center

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 SUMMARY

FOR 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

$$