Prognostic Meteorological Discussion
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FXUS21 KWNC 241844
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT APRIL 24 2014

SYNOPSIS: AT THE START OF THE HAZARDS OUTLOOK, DEEP LOW PRESSURE OVER THE HIGH
PLAINS IS EXPECTED TO MOVE SLOWLY TO THE TENNESSEE AND OHIO VALLEYS, AND THEN
TOWARDS THE MID-ATLANTIC COAST. HIGH PRESSURE IS ANTICIPATED TO BUILD IN BEHIND
THIS AREA OF LOW PRESSURE OVER THE WESTERN U.S. LOW PRESSURE IS FORECAST TO
MOVE SOUTH OF THE ALEUTIANS TO THE GULF OF ALASKA.

HAZARDS

HIGH WINDS FOR PARTS OF THE WEST-CENTRAL, CENTRAL, AND EAST-CENTRAL CONUS,
SUN-THU, APR 27- MAY 1.

HEAVY SNOW FOR PARTS OF THE CENTRAL ROCKIES, SUN-MON, APR 27-28.

HEAVY RAIN FOR PARTS OF THE NORTHERN PLAINS, SUN-MON, APR 27-28.

HEAVY RAIN FOR PARTS OF THE MISSISSIPPI VALLEY, GREAT LAKES, OHIO AND TENNESSEE
VALLEYS, SOUTHERN AND CENTRAL APPALACHIANS, SOUTHEAST, AND MID-ATLANTIC,
SUN-WED, APR 27-30.

SEVERE WEATHER FOR PARTS OF THE CENTRAL AND SOUTHERN PLAINS AND MIDDLE AND
LOWER MISSISSIPPI VALLEYS, SUN, APR 27.

SEVERE WEATHER FOR PARTS OF THE SOUTHERN PLAINS, LOWER AND MIDDLE MISSISSIPPI
VALLEYS, TENNESSEE AND OHIO VALLEYS, AND SOUTHEAST, MON, APR 28.

ENHANCED WILDFIRE RISK FOR PARTS OF EASTERN NEW MEXICO, AND WESTERN TEXAS, SUN,
APR 27.

ENHANCED WILDFIRE RISK FOR PARTS OF SOUTHEASTERN NEW MEXICO AND SOUTHWESTERN
TEXAS, MON, APR 28.

FLOODING IS LIKELY, OCCURRING, OR IMMINENT FOR PARTS OF THE SOUTHEAST, SUN-MON,
APR 27-28.

SEVERE DROUGHT FOR PARTS OF IOWA, GREAT PLAINS, SOUTHWEST, PACIFIC NORTHWEST,
GREAT BASIN, CALIFORNIA, AND HAWAII.

FLOODING POSSIBLE DUE TO ICE JAMS FOR PARTS OF THE YUKON RIVER AND CENTRAL
ALASKA, SUN-TUE, MAY 4-6.

DETAILED SUMMARY

FOR SUNDAY APRIL 27 - THURSDAY MAY 01: THERE ARE SEVERAL FLOOD-RELATED
DESIGNATIONS ON THE MAP IN THE SOUTHEAST. THESE ARE GENERALLY DUE TO WET
ANTECEDENT CONDITIONS. RAINFALL ANTICIPATED OVER PARTS OF THIS REGION NEXT WEEK
MAY PROLONG AND EXACERBATE FLOODING CONCERNS.



THE PRIMARY FOCUS FOR HAZARDS DURING THIS PERIOD INVOLVES AN AREA OF SURFACE
AND UPPER-LEVEL LOW PRESSURE FORECAST TO DEEPEN OVER THE HIGH PLAINS. THIS
SYSTEM IS EXPECTED TO MOVE SLOWLY EASTWARD ACROSS THE MISSISSIPPI VALLEY TO THE
OHIO AND TENNESSE VALLEYS THEN THE MID-ATLANTIC COAST. THIS LOW PRESSURE SYSTEM
IS LIKELY TO BRING HEAVY RAIN (1 TO 4 INCHES) TO PARTS OF THE NORTHERN  PLAINS,
MISSISSIPPI VALLEY, GREAT LAKES, OHIO AND TENNESSEE VALLEYS, SOUTHERN AND
CENTRAL APPALACHIANS, SOUTHEAST, AND MID-ATLANTIC APR 27-30, AND HEAVY SNOW
(6-12 INCHES) TO PARTS OF THE CENTRAL ROCKIES APR 27-28. THE TIGHT PRESSURE
GRADIENT BETWEEN THIS AREA OF LOW PRESSURE AND HIGH PRESSURE BUILDING OVER THE
WESTERN AND CENTRAL CONUS LEADS TO HIGH WINDS (20-40 KTS OR GREATER) FOR PARTS
OF THE WEST-CENTRAL, CENTRAL, AND EAST-CENTRAL CONUS APR 27-MAY 1. HIGH WINDS
AND LOW RELATIVE HUMIDITY LEAD TO AN ENHANCED WILDFIRE RISK FOR PARTS OF
EASTERN NEW MEXICO AND WESTERN TEXAS APR 27, AND SOUTHEASTERN NEW MEXICO AND
SOUTHWESTERN TEXAS APR 28.



AS THE AREA OF LOW PRESSURE MOVES ACROSS THE PLAINS, WARM MOIST AIR IS EXPECTED
TO BE DRAWN NORTHWARD FROM THE GULF OF MEXICO. THIS WILL INCREASE INSTABILITY
ACROSS THE REGION AND SEVERE WEATHER IS ANTICIPATED FOR PARTS OF THE CENTRAL
AND SOUTHERN PLAINS AND MIDDLE AND LOWER MISSISSIPPI VALLEYS APR 27, AND FOR
PARTS OF THE SOUTHERN PLAINS, LOWER AND MIDDLE MISSISSIPPI VALLEYS, OHIO AND
TENNESSEE VALLEYS, AND SOUTHEAST APR 28.

FOR FRIDAY MAY 02 - THURSDAY MAY 08: BY WEEK-2, THE GENERAL CIRCULATION PATTERN
AT 500-HPA IS EXPECTED TO BE OF LOW AMPLITUDE AND FEATURES TROUGHS OVER THE
EASTERN AND WESTERN U.S. AND THE ALEUTIANS, WHILE RIDGES ARE ANTICIPATED OVER
THE WEST-CENTRAL CONUS AND ALASKA. NO SPECIFIC HAZARDS CAN BE DESIGNATED OVER
THE CONUS WITH CONFIDENCE AT THIS RANGE, OTHER THAN CONTINUING LONG-TERM
DROUGHT AREAS.



ACCORDING TO THE U.S. DROUGHT MONITOR VALID ON APRIL 22, SEVERE DROUGHT
COVERAGE HAS INCREASED A PERCENTAGE POINT, FROM 25.20 PERCENT LAST WEEK (CONUS)
TO 26.20 PERCENT THIS WEEK.



FLOODING IS POSSIBLE FOR PORTIONS OF THE YUKON RIVER AND PARTS OF CENTRAL
ALASKA DUE TO ICE JAMS AS RIVER ICE BREAK-UP IS EXPECTED TO COMMENCE DURING THE
PERIOD.

FORECASTER: RANDY SCHECHTER

$$




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