Climate Prediction Center

US HAZARDS ASSESSMENT
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EST JANUARY 13 2009

SYNOPSIS: STRONG HIGH PRESSURE OUT OF CANADA ALONG WITH A PLUMMETING JET STREAM WILL BRING ARCTIC COLD TO MUCH OF THE CENTRAL AND EASTERN U.S. ESPECIALLY BITTER COLD AIR WILL DOMINATE THE MIDWEST, SOUTH, AND EAST ON FRIDAY AND SATURDAY, PRODUCING SUBZERO WIND CHILLS FOR MAJOR METROPOLITAN AREAS FROM CHICAGO TO NEW YORK AND BOSTON. A DUO OF ALBERTA CLIPPER LOWS WILL RAPIDLY PROGRESS EASTWARD ACROSS THE MIDWEST AND MID-ATLANTIC FROM SATURDAY TO TUESDAY, SPREADING SNOW OVER THE MIDWEST AND NORTHEAST. HIGH PRESSURE WILL DOMINATE THE WEST, BRINGING TRANQUIL WEATHER TO MOST OF THE REGION, WHILE DEEP LOW PRESSURE WILL AFFECT SOUTHERN ALASKA ON FRIDAY AND SATURDAY.

HAZARDS

HEAVY RAIN AND SNOW FOR SOUTHERN ALASKA JANUARY 16 - 17.
HIGH WINDS FOR SOUTHERN ALASKA JANUARY 16 - 17.
MUCH BELOW NORMAL TEMPERATURES OVER THE EASTERN HALF OF THE NATION JANUARY 16-21.
SEVERE DROUGHT CONTINUES IN THE SOUTHERN APPALACHIANS, WISCONSIN, THE SOUTHERN PLAINS, AND PARTS OF THE WEST.

DETAILED SUMMARY

FOR FRIDAY JANUARY 16 - SUNDAY JANUARY 18: STRONG HIGH PRESSURE OVER THE MISSOURI VALLEY ON FRIDAY WILL TRACK EASTWARD TO THE EASTERN SEABOARD ON SATURDAY. THE ARCTIC AIR COUPLED WITH BRISK NORTHWESTERLY WINDS WILL PRODUCE DANGEROUSLY LOW WIND CHILLS ACROSS THE MIDWEST AND EAST. TEMPERATURES WILL DROP WELL BELOW ZERO IN CHICAGO BY FRIDAY MORNING, AND READINGS WILL NOT GET OUT OF THE TEENS IN NEW YORK AND BOSTON ON FRIDAY. AN ALBERTA CLIPPER LOW WILL SPREAD SNOW ACROSS THE MIDWEST ON SATURDAY AND OVER THE NORTHEAST ON SUNDAY. FRIDAY AND SATURDAY MORNING SHOULD SEE FREEZING TEMPERATURES AS FAR SOUTH AS THE FLORIDA PENINSULA, POTENTIALLY DAMAGING CROPS AND CITRUS.

HIGH PRESSURE AT THE SURFACE AND ALOFT WILL MAINTAIN MOSTLY DRY AND MILD CONDITIONS ACROSS THE WEST.

ACROSS SOUTHERN ALASKA, A STRONG INFLUX OF MOIST AIR FROM THE GULF OF ALASKA WILL BRING HIGH WINDS AND HEAVY RAIN AND SNOW ON FRIDAY AND SATURDAY.

FOR MONDAY JANUARY 19 - FRIDAY JANUARY 23: A LOW THAT EXITED THE MID-ATLANTIC ON SUNDAY WILL LIKELY INTENSIFY OFF THE NEW ENGLAND COAST ON MONDAY. THE LATEST OPERATIONAL EUROPEAN (ECMWF) MODEL DEVELOPS AN IMPRESSIVE NOR'EASTER WHILE THE GFS SHOWS A MUCH WEAKER SYSTEM. REGARDLESS OF THE DETAILS, THE LOW WILL HELP TO USHER IN ANOTHER SHOT OF COLD AIR FOR THE EAST. BOTH MODELS SHOW LOW PRESSURE OVER NEW ENGLAND ON TUESDAY, LEADING TO STRONG WINDS AND COLD AIR FROM THE EASTERN GREAT LAKES TO THE EAST COAST. THIS SHOULD LEAD TO LOW WIND CHILL READINGS OVER THE I-95 CORRIDOR FROM BOSTON TO DC.

THE GFS MODEL SHOWS THE MEAN TROUGH DIGGING SOUTHWESTWARD TOWARD THE WEST BY FRIDAY, WITH A LOW PRESSURE SYSTEM DEVELOPING IN THE TENNESSEE VALLEY. MUCH COLDER AIR DROPS SOUTHWARD BEHIND THIS STORM AND COVERS MUCH OF THE WEST. THE ECMWF SHOWS THE LOW FARTHER NORTH BUT CONCURS WITH THE FRESH BOUT OF COLD AIR DROPPING OUT OF CANADA.

ANOTHER LOW MAY BRING A BOUT OF STRONG WINDS AND HEAVY RAIN AND SNOW TO ALASKA AT THE START OF THIS PERIOD.

FOR SATURDAY JANUARY 24 - TUESDAY JANUARY 27: MODELS SUGGEST A COLD WEATHER PATTERN FOR MUCH OF THE NATION DURING THIS PERIOD, AS A BROAD UPPER LEVEL TROUGH DOMINATES THE LOWER 48.

FORECASTER: DOUG LECOMTE

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