Prognostic Meteorological Discussion
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FXUS21 KWNC 271940
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MARCH 27 2015

SYNOPSIS: AT THE START OF THE PERIOD, COLD SURFACE HIGH PRESSURE IS EXPECTED
OVER THE EASTERN LOWER 48 STATES. SURFACE LOW PRESSURE IS FORECAST TO MOVE
ALONG THE CENTRAL AND EASTERN U.S./CANADIAN BORDER AS ITS ASSOCIATED COLD FRONT
PROGRESSES ACROSS THE CENTRAL AND EASTERN U.S. A FRONTAL SYSTEM IS ANTICIPATED
TO APPROACH THE NORTHWESTERN PART OF THE NATION. SURFACE LOW PRESSURE IS
FORECAST NEAR THE ALEUTIANS AND GULF OF ALASKA. BY MID-PERIOD, ANOTHER AREA OF
LOW PRESSURE IS EXPECTED TO CROSS THE GREAT LAKES.



HAZARDS

HIGH WINDS FOR PARTS OF THE NORTHEAST, MON-TUE, MAR 30-31.

HIGH WINDS FROM EASTERN MONTANA TO THE GREAT LAKES, WED-FRI, APR 1-3/

FLOODING ONGOING FOR SMALL PORTIONS OF EASTERN TEXAS AND WESTERN TENNESSEE.

SEVERE DROUGHT FOR THE CENTRAL AND SOUTHERN GREAT PLAINS, SOUTHWEST, GREAT
BASIN, CALIFORNIA, THE PACIFIC NORTHWEST, AND SOUTHERN FLORIDA.

DETAILED SUMMARY

FOR MONDAY MARCH 30 - FRIDAY APRIL 03: THIS FORECAST PERIOD IS EXPECTED TO
BEGIN WITH LOW PRESSURE MOVING EASTWARD ACROSS SOUTHEASTERN CANADA.  WHILE NO
PRECIPITATION HAZARDS ARE EXPECTED WITH THIS SYSTEM, IT IS PREDICTED TO HAVE A
STRONG PRESSURE GRADIENT AROUND ITS CENTER, LEADING TO HIGH WINDS FOR PORTIONS
OF THE MID-ATLANTIC AND NEW ENGLAND ON THE 30TH AND 31ST.



IN THE PACIFIC NORTHWEST, A SYSTEM IS EXPECTED TO MOVE ONSHORE SPREADING RAIN
AND HIGH ELEVATION SNOW TO THE COASTAL RANGES OF WASHINGTON STATE AND THE
BITTERROOT MOUNTAINS IN IDAHO.  WHILE THIS PRECIPITATION IS FORECAST TO BE
SIGNIFICANT, IT IS NOT EXPECTED TO REACH HAZARDOUS CRITERIA.  AS THE LOW
PRESSURE MOVES TO THE LEE OF THE ROCKIES, IT IS PREDICTED TO STRENGTHEN,
BRINGING HIGH WINDS FROM THE EASTERN MONTANA TO THE GREAT LAKES FROM THE 1ST
THROUGH THE 3RD.  ALSO, LOCALIZED HEAVY RAIN AND SEVERE WEATHER IS POSSIBLE
ALMOST EVERYWHERE EAST OF THE MISSISSIPPI RIVER IN ADVANCE OF THE STORM`S COLD
FRONT.



UPPER-LEVEL ENERGY THAT IS EXPECTED TO MOVE FROM THE EASTERN PACIFIC INTO THE
SOUTHWEST AND THEN TEXAS, IS FORECAST TO HELP FOCUS HEAVY PRECIPITATION ALONG
THE SOUTHERN EDGE OF THE COLD FRONT IN TEXAS ON THE 1ST AND 2ND.  AT THIS TIME,
THERE IS NO HAZARD DESIGNATED DUE TO UNCERTAINTY IN QPF AMOUNTS, BUT MANY MODEL
SOLUTIONS GIVE HEAVY RAIN (AT LEAST 1 INCH IN 24 HOURS) FOR PARTS OF EASTERN
TEXAS, AND LOUISIANA.

FOR SATURDAY APRIL 04 - FRIDAY APRIL 10: NUMERICAL MODEL SOLUTIONS ARE CALLING
FOR THE PATTERN AT THE BEGINNING OF THIS PERIOD TO BE MOSTLY ZONAL OVER THE
CONUS, BEFORE HINTING AT THE DEVELOPMENT OF AN UPPER-LEVEL TROUGH IN THE WEST
AND A RIDGE IN THE EAST.  THIS PATTERN WOULD FAVOR BELOW NORMAL TEMPERATURES IN
LOCATIONS WEST OF THE ROCKIES, AND ABOVE NORMAL TEMPERATURES EAST OF THE
MISSISSIPPI.



IN ADDITION, SOME MODELS FORECAST AN UPPER-LEVEL LOW TO SIT OVER THE BERING SEA
FOR MOST OF THIS PERIOD.  THIS LOW SUPPORTS MULTIPLE LOW PRESSURE SYSTEMS
IMPACTING THE SOUTHERN AND SOUTHEASTERN COASTS OF THE STATE.  IF THIS SOLUTION
WERE TO VERIFY, A PROLONGED PERIOD OF HEAVY RAIN, HIGH WINDS, AND SIGNIFICANT
WAVES IS LIKELY FOR THESE AREAS.



THE MOST RECENT U.S. DROUGHT MONITOR, VALID MARCH 24, INDICATES A VERY SLIGHT
INCREASE (16.24 TO 16.97) IN THE PERCENTAGE OF LAND IN SEVERE DROUGHT (D2-D4).

FORECASTER: KENNETH PELMAN

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