Re: 1st blizzard of the year ?
Posted by
hanna on 10/5/2012, 10:56 am
SHORT RANGE FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD
430 AM EDT FRI OCT 05 2012
VALID 12Z FRI OCT 05 2012 - 12Z SUN OCT 07 2012
...THE COLDEST AIR MASS OF THE SEASON CONTINUES TO SURGE SOUTH AND
EAST THROUGH THE NATION...
...SNOW EXCEEDING A HALF A FOOT IS POSSIBLE ACROSS SOUTHEASTERN
WYOMING/NEBRASKA PANHANDLE THROUGH SUNDAY MORNING...
THE PATTERN ACROSS THE NATION REMAINS WELL AMPLIFIED AS AN UPPER
TROUGH WILL EASILY COVER THE EASTERN TWO-THIRDS OF THE CONUS BY
THE END OF THE WEEKEND. MEANWHILE...A REX BLOCK IS FORECAST TO SET
UP ACROSS EASTERN PACIFIC WITH AN UPPER LOW OFFSHORE OF NORTHERN
CALIFORNIA BRIDGED TO THE NORTH BY AN EXPANSIVE RIDGE OF HIGH
PRESSURE. THE PRIMARY THEMES DURING THE NEXT COUPLE OF DAYS WILL
BE BELOW NORMAL TEMPERATURES OVER MUCH OF THE COUNTRY AS COLD
CANADIAN AIR HAS PLUNGED WELL BELOW THE 40 DEGREE LATITUDE.
ADDITIONALLY...THE MOISTURE CONTENT IN THE ATMOSPHERE WILL BE
RATHER LIMITED WHICH WILL MAINTAIN THE HIGHEST RAINFALL AMOUNTS
ALONG THE POTENT FRONTAL BOUNDARY ADVANCING INTO THE OHIO RIVER
VALLEY.
THE FIRST SHOT OF COLD AIR FOR THE SEASON IS DEFINITELY APPARENT
IN THE FORECAST HIGHS ACROSS THE MIDDLE OF THE COUNTRY. HIGHS ARE
EXPECTED TO REMAIN IN THE 40S THE NEXT COUPLE OF DAYS ACCOMPANIED
BY DRY NORTHWESTERLY FLOW WHICH WILL MAKE IT EVEN FEEL COOLER AT
TIMES. THESE LOCATIONS CAN ALSO EXPECT DIMINISHING OVERNIGHT
TEMPERATURES AS A STRONG SURFACE RIDGE DESCENDS SOUTHWARD FROM
LOWER SASKATCHEWAN. ADEQUATE CONDITIONS FOR RADIATIONAL COOLING
SHOULD SUPPORT LOWS DROPPING IN THE 20S WHICH HAS LEAD TO A
VARIETY OF FREEZE-RELATED WARNINGS BEING ISSUED BY LOCAL FORECAST
OFFICES. THIS SURGE OF COLD AIR IS EXPECTED TO CONTINUE PUSHING
SOUTH AND EAST INTO THE WEEKEND WHICH WILL EVENTUALLY PUT AN END
TO THE ANOMALOUS WARMTH EXPERIENCED IN THE EAST. WHILE THE FRONTAL
PASSAGE WILL TAKE PLACE ON SATURDAY ALONG THE EASTERN
SEABOARD...THE COLDEST AIR WILL NOT ARRIVE UNTIL SUNDAY WHICH IS
FORECAST TO BE ACCOMPANIED BY A THREAT FOR RAIN SHOWERS. IN
FACT...MUCH OF THE PRECIPITATION WITH THIS SYSTEM WILL BE
POST-FRONTAL WITH THE BOUNDARY ITSELF REMAINING MORE DRY IN
NATURE. AS MENTIONED EARLIER...THIS POST-FRONTAL AIR MASS WILL BE
QUITE CHILLY WHICH SHOULD LEAD TO A RATHER COLD RAIN AT TIMES.
ADDITIONALLY...SOME LAKE-ENHANCED RAIN SHOWERS WILL BE POSSIBLE
DOWNWIND OF THE GREAT LAKES ALBEIT WITH RATHER LIGHT PRECIPITATION
AMOUNTS.
AS SNOW LEVELS CONTINUE TO DROP ACROSS THE CENTRAL ROCKIES...AN
UPSLOPE FLOW SHOULD AID IN DEVELOPING WINTRY PRECIPITATION FROM
SOUTH-CENTRAL MONTANA THROUGH MUCH OF WYOMING AND INTO THE CENTRAL
HIGH PLAINS. THE HPC WINTER WEATHER DESK IS ADVERTISING IN UPWARDS
OF 6 INCHES OF SNOW ACROSS SOUTHEASTERN WYOMING/WESTERN NEBRASKA
THROUGH SUNDAY MORNING.
RUBIN-OSTER
GRAPHICS AVAILABLE AT www.hpc.ncep.noaa.gov/basicwx/basicwx_wbg.php |
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1st blizzard of the year ? -
cypresstx,
10/3/2012, 7:05 am Post A Reply
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