Prognostic Meteorological Discussion
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FXUS21 KWNC 011852
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT APRIL 01 2015

SYNOPSIS: AT THE START OF THE PERIOD, SURFACE LOW PRESSURE OVER THE NORTHEAST
AND ITS ASSOCIATED FRONTAL SYSTEMS ARE FORECAST TO MOVE OFF THE EAST COAST. A
SECOND COLD FRONT IS EXPECTED TO MOVE FROM THE NORTHERN PLAINS/UPPER
MISSISSIPPI VALLEY TO THE NORTHEAST STATES AND OHIO VALLEY. HIGH PRESSURE OVER
THE CENTRAL U.S. IS EXPECTED TO MOVE TO THE EASTERN PART OF THE NATION AS
SURFACE LOW PRESSURE DEVELOPS OVER THE GREAT BASIN/CENTRAL ROCKIES. AREAS OF
UPPER-LEVEL LOW PRESSURE ARE FORECAST TO MOVE ACROSS THE NORTHWEST U.S. APR
5-7. ANOTHER AREA OF SURFACE LOW PRESSURE IS FORECAST TO MOVE FROM THE GREAT
BASIN TO THE NORTH-CENTRAL U.S. DURING THIS TIMEFRAME. DURING THE PERIOD, A
SERIES OF AREAS OF SURFACE LOW PRESSURE ARE ANTICIPATED TO MOVE FROM THE BERING
SEA TOWARDS THE NORTHERN GULF OF ALASKA AS HIGH PRESSURE BUILDS NORTH OF THE
STATE. EARLY IN THE WEEK 2 PERIOD, AN AREA OF UPPER-LEVEL LOW PRESSURE IS
FORECAST TO MOVE FROM THE NORTH-CENTRAL U.S. TO THE NORTHEAST STATES.

HAZARDS

HEAVY RAIN FOR PARTS OF THE LOWER AND MIDDLE MISSISSIPPI VALLEYS AND OHIO AND
TENNESSEE VALLEYS, MON-WED, APR 6-8.

HEAVY SNOW FOR PARTS OF THE GREAT LAKES AND INTERIOR PORTIONS OF THE NORTHEAST
STATES, SAT, APR 4.

HEAVY PRECIPITATION FOR PARTS OF NORTHERN CALIFORNIA, MON-TUE, APR 6-7.

HIGH WINDS FOR PARTS OF THE EAST COAST, SAT-SUN, APR 4-5.

HIGH WINDS FOR PARTS OF THE SOUTHWEST, CENTRAL GREAT BASIN, CENTRAL AND
SOUTHERN ROCKIES, AND CENTRAL AND SOUTHERN PLAINS, SUN-MON, APR 5-6.

HIGH WINDS FOR PARTS OF THE CALIFORNIA COAST, SAT, APR 4.

HIGH WINDS FOR PARTS OF THE ALEUTIANS, SOUTHERN COAST OF ALASKA, AND THE ALASKA
PANHANDLE, MON-TUE, APR 6-7.

HIGH WINDS FOR PARTS OF NORTHWEST ALASKA, MON-TUE, APR 6-7.

HEAVY PRECIPITATION FOR PARTS OF THE ALASKA PANHANDLE, MON-TUE, APR 6-7.

MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF NORTHERN NEW ENGLAND, SUN-MON, APR
5-6.

SLIGHT CHANCE OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF THE UPPER
MISSISSIPPI VALLEY, GREAT LAKES, AND NORTHEAST, THU-MON, APR 9-13.

MODERATE CHANCE OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF NORTHERN MAINE,
THU-FRI, APR 9-10.

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

DETAILED SUMMARY

FOR SATURDAY APRIL 04 - WEDNESDAY APRIL 08: LOW PRESSURE AND ITS ASSOCIATED
COLD FRONT ARE FORECAST TO MOVE OFF THE EAST COAST. THIS IS EXPECTED TO CAUSE
HIGH WINDS (IN EXCESS OF 30 KNOTS) FOR PARTS OF THE EAST COAST APR 4-5. AFTER
THE FRONT CROSSES THE NORTHEAST U.S., HEAVY SNOWFALL (IN EXCESS OF 4 INCHES IN
24 HOURS) IS POSSIBLE BEHIND THE FRONT NEAR THE GREAT LAKES AND INTERIOR NEW
ENGLAND APR 4. MUCH BELOW NORMAL TEMPERATURES (NEGATIVE ANOMALIES OF 10-15
DEGREES F) ARE ANTICIPATED FOR PARTS OF NORTHERN NEW ENGLAND APR 5-6.



AN AREA OF LOW PRESSURE MOVING FROM THE NORTHERN ROCKIES TO THE
NORTHERN/CENTRAL PLAINS WILL DRAW WARM MOIST AIR NORTHWARD. THIS LEADS TO HEAVY
RAIN (IN EXCESS OF 1 INCH IN 24 HOURS) FOR PARTS OF THE LOWER AND MIDDLE
MISSISSIPPI VALLEYS AND OHIO AND TENNESSEE VALLEYS APR 6-8. SEVERE WEATHER IS
ALSO POSSIBLE OVER THE REGION BUT LARGE MODEL SPREAD PRECLUDES SPECIFYING A
HAZARD SHAPE AT THE CURRENT TIME. BEHIND THE AREA OF LOW PRESSURE, HIGH WINDS
(IN EXCESS OF 30 KNOTS) ARE EXPECTED FOR PARTS OF THE SOUTHWEST, CENTRAL GREAT
BASIN, CENTRAL AND SOUTHERN ROCKIES, AND CENTRAL AND SOUTHERN PLAINS APR 5-6.



OFFSHORE FLOW AND HIGH WINDS (IN EXCESS OF 30 KNOTS) ARE ANTICIPATED FOR PARTS
OF THE CALIFORNIA COAST APR 4.



A LONGWAVE TROUGH APPROACHING THE NORTHWEST CONUS IS EXPECTED TO BRING
UNSETTLED WEATHER TO THE REGION. SHORTWAVES PROAGATING THROUGH THE TROUGH LEADS
TO HEAVY PRECIPITATION (RAINFALL IN EXCESS OF 1 INCHES IN 24 HOURS AT LOWER
ELEVATIONS, SNOWFALL IN EXCESS OF 4 INCHES IN 24 HOURS AT THE HIGHEST
ELEVATIONS) APR 6-7.



MARGINAL CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED OVER PORTIONS OF THE
WEST-CENTRAL AND SOUTH-CENTRAL CONUS APR 4-7 BUT MODEL UNCERTAINTY PRECLUDES
THE SPECIFICATION OF HAZARD SHAPES AT THE CURRENT TIME.



AREAS OF LOW PRESSURE ARE FORECAST TO MOVE ACROSS THE BERING SEA TO THE GULF OF
ALASKA. HIGH WINDS (IN EXCESS OF 40 KNOTS) ARE POSSIBLE FOR PARTS OF THE
ALEUTIANS, SOUTHERN COAST OF ALASKA, THE ALASKA PANHANDLE, AND NORTHWEST ALASKA
APR 6-7. BLOWING SNOW MAY REDUCE VISIBILITIES OVER NORTHWEST ALASKA DURING THIS
TIMEFRAME. HEAVY PRECIPITATION (RAINFALL IN EXCESS OF 2 INCHES AT LOWER
ELEVATIONS, SNOWFALL IN EXCESS OF 8 INCHES IN 24 HOURS AT HIGHER ELEVATIONS) IS
POSSIBLE OVER PARTS OF THE ALASKA PANHANDLE APR 6-7.

FOR THURSDAY APRIL 09 - WEDNESDAY APRIL 15: AN UPPER-LEVEL TROUGH EXPECTED OVER
SOUTHEASTERN CANADA LEADS TO A SLIGHTLY ELEVATED CHANCE OF MUCH BELOW NORMAL
TEMPERATURES FOR PARTS OF THE UPPER MISSISSIPPI VALLEY, GREAT LAKES, AND
NORTHEAST APR 9-13, AND A MODERATE CHANCE OF MUCH BELOW NORMAL TEMPERATURES FOR
PARTS OF NORTHERN MAINE APR 9-10.



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

FORECASTER: RANDY SCHECHTER

$$



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