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FXUS21 KWNC 221919
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MAY 22 2013

SYNOPSIS: JUST PRIOR TO THE START OF THE PERIOD, A COLD FRONT IS PREDICTED TO
MOVE OFF THE ATLANTIC AND GULF COASTS, WITH A LOW PRESSURE CENTER FORECAST TO
FORM ALONG THE FRONT NEAR THE NEW JERSEY COAST. HIGH PRESSURE IS EXPECTED TO
BUILD IN BEHIND THIS COLD FRONT ACROSS THE EASTERN HALF OF THE CONTIGUOUS
UNITED STATES. A STATIONARY FRONT OVER THE CENTRAL GREAT PLAINS AND MIDDLE
MISSISSIPPI VALLEY IS ANTICIPATED TO TRANSFORM INTO A WARM FRONT, THEN SLOWLY
TRACK NORTHWARD. BY THE MIDDLE OF THE HAZARDS OUTLOOK, A FRONTAL SYSTEM IS
FORECAST TO APPROACH THE WEST COAST. IN ALASKA, A LOW PRESSURE SYSTEM OVER THE
CENTRAL ALEUTIANS IS PREDICTED TO SHIFT EASTWARD INTO THE NORTHERN GULF OF
ALASKA.

HAZARDS

HEAVY RAIN FOR IOWA AND PORTIONS OF ADJACENT STATES, SAT-SUN, MAY 25-26.

HIGH WINDS ALONG THE MID-ATLANTIC AND SOUTHERN NEW ENGLAND COASTS, SAT-SUN, MAY
25-26.

MUCH ABOVE NORMAL TEMPERATURES FOR THE ALASKA PANHANDLE AND SOUTHEASTERN
PORTIONS OF THE MAINLAND, SAT-WED, MAY 25-29.

ENHANCED WILDFIRE RISK FOR NORTHERN ARIZONA, SAT, MAY 25.

RIVER FLOODING OCCURRING OR IMMINENT IN NORTHERN NORTH DAKOTA AND THE MIDDLE
MISSISSIPPI VALLEY, SAT-SUN, MAY 25-26.

RIVER FLOODING LIKELY IN CENTRAL NORTH DAKOTA AND EASTERN IOWA, SAT-SUN, MAY
25-26.

RIVER FLOODING POSSIBLE FOR EXTREME EASTERN IOWA, SAT-SUN, MAY 25-26.

RIVER FLOODING POSSIBLE ACROSS CENTRAL AND SOUTHWESTERN ALASKA, SAT-TUE, MAY
25-28.

RIVER FLOODING POSSIBLE IN WESTERN ALASKA, THU-WED, MAY 30-JUNE 5.

RIVER FLOODING POSSIBLE IN SOUTHWESTERN ALASKA, THU-SUN, MAY 30-JUNE 2.

SEVERE DROUGHT FOR PARTS OF NORTHERN FLORIDA, GREAT PLAINS, RIO GRANDE VALLEY,
ROCKIES, SOUTHWEST, GREAT BASIN, CALIFORNIA, AND HAWAII.

DETAILED SUMMARY

FOR SATURDAY MAY 25 - WEDNESDAY MAY 29: AREAS OF HEAVY RAIN (2-3 INCHES) ARE
PREDICTED OVER THE CENTRAL CORN BELT DURING THIS PERIOD, IN ADVANCE OF A WARM
FRONT. WITH A 500-HPA TROUGH FORECAST OVER THE WEST, AND A 500-HPA RIDGE
FORECAST OVER THE CENTRAL CONUS, ELEVATED CHANCES FOR SEVERE WEATHER ACROSS THE
CENTRAL GREAT PLAINS OR CRITICAL WILDFIRE AREAS IN THE SOUTHWEST EXIST. THERE
IS TOO MUCH UNCERTAINTY AT THIS TIME REGARDING THE TIMING OF SHORT-WAVE TROUGHS
EJECTING OUT OF THE WEST COAST LONG-WAVE TROUGH TO WARRANT A SEVERE WEATHER
AREA IN THE PLAINS. HOWEVER, THERE IS SUFFICIENT SUPPORT FOR AN ENHANCED
WILDFIRE RISK OVER NORTHERN ARIZONA, RELATED TO THE EXPECTATION OF STRONGER
WINDS ALOFT AND DEEP VERTICAL MIXING IN THE BOUNDARY LAYER.



IN THE PAST WEEK, ANYWHERE FROM 2-6 INCHES OF RAIN HAVE FALLEN ACROSS NORTHERN
AND SOUTH-CENTRAL PORTIONS OF BOTH THE GREAT PLAINS AND THE MISSISSIPPI VALLEY.
ABOUT 10 FLOOD AREAS ARE HIGHLIGHTED ON THE MAP OVER THE CENTRAL CONUS, DUE TO
THIS RECENT RAIN AND THE EXPECTATION OF MORE RAIN DURING THIS PERIOD.



NEAR THE BEGINNING OF THE HAZARDS OUTLOOK, A COLD FRONT IS EXPECTED TO MOVE OFF
THE EAST COAST, WITH AN AREA OF LOW PRESSURE DEVELOPING ALONG THIS FRONT NEAR
THE NEW JERSEY COAST. WINDS OF 20-30 KNOTS ARE FORECAST FOR THE MID-ATLANTIC
AND SOUTHERN NEW ENGLAND COASTS IN ASSOCIATION WITH THIS SYSTEM AS IT GRADUALLY
MOVES OUT OVER THE WESTERN ATLANTIC.



IN ALASKA, AN AREA OF LOW PRESSURE IS PREDICTED TO MOVE FROM THE CENTRAL
ALEUTIANS EAST-SOUTHEASTWARD ACROSS THE GULF OF ALASKA. A SURFACE RIDGE OF HIGH
PRESSURE IS ANTICIPATED OVER SOUTHEASTERN PORTIONS OF ALASKA. MUCH ABOVE NORMAL
TEMPERATURES ARE PROJECTED FOR THE PANHANDLE REGION AND SOUTHEASTERN PART OF
THE MAINLAND. IN ADDITION, WITH THE EXPECTED CHANGE FROM UNSEASONABLY COLD TO
UNSEASONABLY WARM WEATHER, THERE ARE FLOODING CONCERNS ALONG MAJOR RIVERS (FOR
EXAMPLE, THE YUKON AND KUSKOKWIM RIVERS) IN CENTRAL AND SOUTHWESTERN ALASKA DUE
TO MELTING SNOW AND ICE JAMS. OF NOTE IS THE VERY RECENT BREAKUP OF RIVER ICE
IN THE TANANA RIVER NEAR NENANA, AK. THIS IS THE LATEST RECORDED RIVER ICE
BREAKUP FOR THE TANANA RIVER SINCE RECORD-KEEPING BEGAN IN 1917. THE PREVIOUS
RECORD WAS MAY 20, 1964.

FOR THURSDAY MAY 30 - WEDNESDAY JUNE 05: THE ONLY HAZARDOUS AREAS HIGHLIGHTED
ON THE WEEK 2 MAP AT THIS TIME ARE THE CONTINUING FLOOD AND DROUGHT AREAS.
THERE ARE TWO ITEMS WHICH WARRANT FURTHER MONITORING DURING THE NEXT FEW DAYS.
THE FIRST INVOLVES THE POTENTIAL FOR MUCH ABOVE NORMAL TEMPERATURES FROM THE
CENTRAL HIGH PLAINS EASTWARD ACROSS THE NORTH-CENTRAL MISSISSIPPI VALLEY AND
GREAT LAKES REGION. HOWEVER, THE LATEST MODEL RUNS PREDICT THE ASSOCIATED
500-HPA RIDGE TO BE MORE PROGRESSIVE AND TRANSITORY THAN BEFORE.  THE SECOND
ITEM INVOLVES THE POSSIBILITY OF A TROPICAL SYSTEM DEVELOPING OVER THE WESTERN
CARIBBEAN AND MOVING NORTHWARD INTO THE GULF OF MEXICO, AS INDICATED BY CPC`S
GLOBAL TROPICS HAZARDS AND BENEFITS OUTLOOK AT:

HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PRECIP/CWLINK/GHAZARDS/IMAGES/GTH_FULL.PNG



ACCORDING TO THE U.S. DROUGHT MONITOR VALID MAY 14, SEVERE (D2) TO EXCEPTIONAL
(D4) DROUGHT COVERAGE ACROSS THE CONTINENTAL U.S. DECREASED SLIGHTLY TO 32
PERCENT WITH THE MOST IMPROVEMENT NOTED IN SOUTHERN MINNESOTA.

FORECASTER: ANTHONY ARTUSA

$$