Prognostic Meteorological Discussion
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FXUS21 KWNC 222107
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT APRIL 22 2014

SYNOPSIS: AT THE START OF THE HAZARDS OUTLOOK, LOW PRESSURE OVER THE GREAT
LAKES IS FORECAST TO MOVE TOWARDS NEW ENGLAND. HIGH PRESSURE IS ANTICIPATED TO
BUILD IN BEHIND THIS AREA OF LOW PRESSURE OVER THE HIGH PLAINS, MISSISSIPPI
VALLEY AND GREAT LAKES. SURFACE AND UPPER-LEVEL LOW PRESSURE WILL AFFECT THE
WESTERN U.S. BY LATE THIS WEEKEND, LOW PRESSURE IS EXPECTED TO FORM OVER THE
CENTRAL PLAINS AND MOVE SLOWLY TOWARDS THE OHIO AND TENNESSE VALLEYS AS ITS
TRAILING COLD FRONT MOVES ACROSS THE SOUTHERN PLAINS. AREAS OF LOW PRESSURE ARE
FORECAST TO MOVE FROM SOUTH OF THE ALEUTIANS TO THE GULF OF ALASKA.

HAZARDS

HIGH WINDS FOR PARTS OF THE GREAT LAKES, FRI, APR 25.

HIGH WINDS FOR PARTS OF THE SOUTHWEST, PLAINS, ROCKIES, UPPER AND MIDDLE
MISSISSIPPI VALLEYS, AND GREAT LAKES, FRI-TUE, APR 25-29.

HEAVY SNOW FOR PARTS OF THE NORTHERN SIERRAS, FRI, APR 25.

HEAVY SNOW FOR PARTS OF THE NORTHERN AND CENTRAL ROCKIES, FRI-SAT, APR 25-26.

HEAVY RAIN FOR PARTS OF THE MIDDLE AND LOWER MISSISSIPPI VALLEYS, OHIO AND
TENNESSEE VALLEYS, SOUTHERN APPALACHIANS, AND SOUTHEAST MON-TUE, APR 28-29.

SEVERE WEATHER FOR PARTS OF THE CENTRAL AND SOUTHERN PLAINS, SAT, APR 26.

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

ENHANCED WILDFIRE RISK FOR PARTS OF NORTHWEST ARIZONIA, FRI, APR 25.

ENHANCED WILDFIRE RISK FOR PARTS OF CENTRAL AND EASTERN NEW MEXICO, SAT, APR 26.

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

FLOODING IS LIKELY, POSSIBLE, OCCURRING, OR IMMINENT FOR PARTS OF THE SOUTHEAST
AND LOWER MISSISSIPPI VALLEY, FRI-SAT, APR 25-26.

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, WED-SUN, APR
30-MAY 4.

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

DETAILED SUMMARY

FOR FRIDAY APRIL 25 - TUESDAY APRIL 29: THERE ARE A SIGNIFICANT NUMBER OF
FLOOD-RELATED DESIGNATIONS ON THE MAP IN THE SOUTHEAST. THESE ARE GENERALLY DUE
TO WET ANTECEDENT CONDITIONS.



A TIGHT PRESSURE GRADIENT ASSOCIATED WITH LOW PRESSURE FORECAST OVER THE GREAT
LAKES LEADS TO HIGH WINDS (20-30 KTS OR GREATER) FOR PARTS OF THE GREAT LAKES
APR 25.



LOW PRESSURE AT THE SURFACE AND ALOFT WILL LIKELY AFFECT THE WESTERN CONUS.
HEAVY SNOW (6-12 INCHES OR GREATER) IS POSSIBLE FOR HIGHER ELEVATIONS OF THE
NORTHERN SIERRAS APR 25, AND FOR PARTS OF THE NORTHERN AND CENTRAL ROCKIES APR
25-26.



LOW PRESSURE IS FORECAST TO DEEPEN AND MOVE FROM THE GREAT BASIN TO THE CENTRAL
AND SOUTHERN PLAINS AND THEN THE OHIO AND TENNESSEE VALLEYS. HIGH WINDS (20-40
KTS) ARE ANTICIPATED FOR PARTS OF THE SOUTHWEST, PLAINS, ROCKIES, UPPER AND
MIDDLE MISSISSIPPI VALLEYS, AND GREAT LAKES APR 25-29. THE AREA OF LOW PRESSURE
IS FORECAST TO CAUSE HEAVY RAIN (2-3 INCHES)FOR PARTS OF THE  MIDDLE AND LOWER
MISSISSIPPI VALLEYS, OHIO AND TENNESSEE VALLEYS, SOUTHERN APPALACHIANS, AND
SOUTHEAST APR 28-29. SEVERE WEATHER IS EXPECTED FOR PARTS OF THE CENTRAL AND
SOUTHERN PLAINS APR 26, AND FOR PARTS OF THE CENTRAL AND SOUTHERN PLAINS AND
LOWER AND MIDDLE MISSISSIPPI VALLEYS APR 27.



AN ACTIVE METEOROGOLOGICAL FIRE WEATHER PATTERN FEATURING WIDESPREAD STRONG
WINDS AND LOW RELATIVE HUMIDITY WILL LIKELY DEVELOP AND AFFECT PORTIONS OF THE
SOUTHWESTERN CONUS AND SOUTHERN HIGH PLAINS LATE THIS WEEK AND THIS WEEKEND.

FOR WEDNESDAY APRIL 30 - TUESDAY MAY 06: BY WEEK-2, THE GENERAL CIRCULATION
PATTERN AT 500-HPA IS EXPECTED TO FEATURE TROUGHS OVER THE EASTERN 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 15, SEVERE DROUGHT
COVERAGE HAS INCREASED NEARLY A PERCENTAGE POINT, FROM 24.23 PERCENT LAST WEEK
(CONUS) TO 25.20 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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