Valid Monday, April 21, 2014 to Friday, May 02, 2014

Summary of Forecasts and Hazards

US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT APRIL 18 2014

SYNOPSIS: AT THE START OF THE HAZARDS OUTLOOK, SEVERAL WEAK WEATHER DISTURBANCES ARE FORECAST TO MOVE ACROSS THE CONTIGUOUS U.S. BY THE MIDDLE OF NEXT WEEK, A MORE SIGNIFICANT STORM SYSTEM IS PREDICTED TO DEVELOP OVER THE CENTRAL PORTION OF THE COUNTRY. SEVERAL NORTHERN PACIFIC STORM SYSTEMS ARE ANTICIPATED TO INFLUENCE THE SOUTHERN COASTAL AREAS OF ALASKA.

HAZARDS

• HEAVY RAIN ACROSS PARTS OF THE NORTHERN PLAINS AND NORTH-CENTRAL MISSISSIPPI VALLEY, WED-THU, APR 23-24.
• FLOODING IS OCCURRING, IMMINENT, OR LIKELY FOR THE CENTRAL GULF COAST STATES AND NORTHERN PARTS OF FLORIDA, LOWER MICHIGAN, PARTS OF NEW YORK AND NEW ENGLAND, AND OVER NORTHEASTERN NORTH DAKOTA AND ADJACENT NORTHWESTERN MINNESOTA (THE RED RIVER OF THE NORTH), MON-TUE, APR 21-22.
• HIGH WINDS ARE PREDICTED FOR MUCH OF NEVADA, SOUTHWEST UTAH, ARIZONA AND NEW MEXICO, TUE-WED, APR 22-23.
• ENHANCED WILDFIRE RISK FOR PARTS OF THE SOUTHWEST, TUE-WED, APR 22-23.
• HIGH WINDS FOR PARTS OF THE NORTHERN AND CENTRAL PLAINS, WED, APR 23.
• SEVERE DROUGHT FOR PARTS OF IOWA, GREAT PLAINS, SOUTHWEST, PACIFIC NORTHWEST, GREAT BASIN, CALIFORNIA, AND HAWAII.

DETAILED SUMMARY

FOR MONDAY APRIL 21 - FRIDAY APRIL 25: THERE ARE A SIGNIFICANT NUMBER OF FLOOD-RELATED DESIGNATIONS ON THE MAP IN THE EAST. THESE ARE GENERALLY DUE TO WET ANTECEDENT CONDITIONS, ANTICIPATED RAINFALL DURING (OR IN THE TWO DAYS PRIOR TO) THIS PERIOD, OR SNOW MELT (IN NORTHERN AREAS).

BY THE MIDDLE OF NEXT WEEK, A SIGNIFICANT 500-HPA TROUGH IS PREDICTED BY MOST MODELS TO MOVE ACROSS THE WESTERN CONUS. HIGH WINDS (20-30 KTS OR MORE) ARE FORECAST FOR NEVADA, SOUTHWEST UTAH, ARIZONA AND NEW MEXICO, IN CONNECTION WITH THIS TROUGH. ADDITIONALLY, HIGH WINDS COMBINED WITH DRY FUEL AND LOW RELATIVE HUMIDITY WILL INCREASE CHANCES FOR CRITICAL FIRE WEATHER. AS THIS PREDICTED TROUGH MOVES OUT INTO THE PLAINS, THERE IS ALSO THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS TO DEVELOP. HOWEVER, THE LATEST GUIDANCE SUGGESTS THAT ANY STORMS THAT DO FORM COULD BE LIMITED BY THE AMOUNT OF UNSTABLE, LOW-LEVEL GULF MOISTURE AVAILABLE TO THEM. THAT SAID, SHEAR PARAMETERS COULD BE IMPRESSIVE, SO THIS SITUATION NEEDS TO BE CAREFULLY MONITORED. HIGH WINDS IN EXCESS OF 30 KNOTS ARE EXPECTED AHEAD OF THE SURFACE LOW ACROSS THE CENTRAL AND NORTHERN PLAINS ON WEDNESDAY.

ABOVE-NORMAL TEMPERATURES ARE EXPECTED AHEAD OF THAT SYSTEM AS WELL ACROSS THE SOUTH-CENTRAL CONUS, THOUGH DAYTIME HIGHS PEAKING IN THE 80S TO NEAR 90 HARDLY SEEMS HAZARDOUS GIVEN THE TIME OF YEAR.

IN THE NORTHWEST, RAINFALL TOTALING 0.75-1.5 INCHES IS POSSIBLE LATER IN THIS PERIOD, THOUGH THIS TOO IS NOT CONSIDERED HAZARDOUS.

SEVERAL LOW PRESSURE SYSTEMS ARE FORECAST TO MOVE ACROSS THE ALEUTIANS AND GULF OF ALASKA, BRINGING PRECIPITATION TO MUCH OF THE SOUTHERN ALASKA COAST, ESPECIALLY THE PANHANDLE. AT THIS TIME, NO HAZARDS ARE DEPICTED FOR THE STATE.

FOR SATURDAY APRIL 26 - FRIDAY MAY 02: BY WEEK-2, THE GENERAL CIRCULATION PATTERN AT 500-HPA IS EXPECTED TO FEATURE A FAST, WESTERLY JET ACROSS THE NORTHERN PACIFIC, WHICH WILL DIRECT ABUNDANT MOISTURE INTO THE WEST COAST. ANOMALOUSLY WET CONDITIONS COULD EXTEND FAIRLY FAR SOUTH IN CALIFORNIA AND POINTS EAST. A RIDGE IS FORECAST TO EXTEND FROM THE WEST-CENTRAL CONUS NORTHWARD TO NORTHWESTERN NORTH AMERICA. NO SPECIFIC HAZARDS CAN BE DESIGNATED 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.

FORECASTER: STEPHEN BAXTER

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