Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2
000
FXUS21 KWNC 271858
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT AUGUST 27 2015

SYNOPSIS: EARLY IN THE PERIOD A FRONT IS EXPECTED TO BE STALLED ACROSS NORTHERN
FLORIDA. TROPICAL STORM ERIKA CURRENTLY SOUTHEAST OF PUERTO RICO IS EXPECTED TO
STRENGHTEN TO A HURRICANE AS IT TRACKS ACROSS THE BAHAMAS THIS WEEKEND. SURFACE
LOW PRESSURE OVER THE GULF OF ALASKA ON SUNDAY IS EXPECTED TO CAUSE ONSHORE
FLOW OVER PARTS OF THE ALASKA PANHANDLE AND THE PACIFIC NORTHWEST DURING SUNDAY
AND MONDAY. STRONG NORTHERLY FLOW IS EXPECTED OVER WESTERN ALASKA DUE TO THE
CIRCULATION AROUND THE AREA OF SURFACE LOW PRESSURE FORECAST OVER THE GULF OF
ALASKA. DURING WEEK-2, AN AREA OF UPPER-LEVEL HIGH PRESSURE IS ANTICIPATED TO
DEVELOP OVER ALASKA WHILE UPPER-LEVEL HIGH PRESSURE BUILDS OVER THE CENTRAL AND
EAST-CENTRAL PORTIONS OF THE LOWER 48 STATES. AREAS OF UPPER-LEVEL LOW PRESSURE
ARE EXPECTED TO BE EMBEDDED WITHIN THIS AREA OF UPPER-LEVEL HIGH PRESURE.

HAZARDS

FLOODING POSSIBLE FOR PARTS OF IOWA.

FLOODING POSSIBLE FOR PARTS OF WEST-CENTRAL FLORIDA.

HEAVY RAIN FOR MUCH OF THE FLORIDA PENINSULA AND PARTS OF THE SOUTHEAST AND
MID-ATLANTIC COASTS SUN-THU, AUG 30-SEP 3.

HIGH WINDS FOR MUCH OF THE FLORIDA PENINSULA AND PARTS OF THE SOUTHEAST AND
MID-ATLANTIC COASTS SUN-THU, AUG 30-SEP 3.

HIGH WINDS FOR PARTS OF THE ALASKAN PENINSULA, SOUTH AND WESTERN COASTAL
ALASKA, AND THE ALASKA PANHANDLE, SUN-MON, AUG 30-31.

SIGNIFICANT WAVES FOR NORTHERN PARTS OF THE SEWARD PENINSULA, SUN, AUG 30.

HEAVY RAIN FOR PARTS OF THE ALASKA PANHANDLE SUN, AUG 30.

MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF CENTRAL AND EASTERN ALASKA,
SUN-WED, AUG 30-SEP 2.

A SLIGHT RISK OF MUCH ABOVE NORMAL TEMPERATURES FOR PARTS OF THE
CENTRAL/SOUTHERN GREAT PLAINS, LOWER AND MIDDLE MISSISSIPPI VALLEYS, TENNESSEE
AND OHIO VALLEYS, AND SOUTHEAST, FRI-THU, SEP 4-10.

A MODERATE RISK OF MUCH ABOVE NORMAL TEMPERATURES FOR PARTS OF THE SOUTHERN
PLAINS, FRI, SEP 4.

A SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF SOUTHEASTERN
ALASKA, FRI, SEP 4.

SEVERE DROUGHT FOR PARTS OF THE WESTERN THIRD OF THE CONUS, SOUTHERN GREAT
PLAINS, LOWER MISSISSIPPI VALLEY, SOUTHEAST, AND HAWAII.

DETAILED SUMMARY

FOR SUNDAY AUGUST 30 - THURSDAY SEPTEMBER 03: A STALLED FRONT ACROSS FLORIDA
WILL ACT AS A FOCUSING MECHANISM FOR SHOWERS AND THUNDERSTORMS. IN ADDITION,
TROPICAL STORM ERIKA WHICH ON AUG 27 IS LOCATED NEAR 17N 63W IS FORECAST TO
STRENGHTEN TO A HURRICANE AND BE NEAR SOUTHEASTERN FLORIDA MONDAY MORNING.
ERIKA IS THEN EXPECTED TO MOVE SLOWLY NORTH-NORTHWESTWARD MONDAY AND TUESDAY.
HEAVY RAIN (IN EXCESS OF 1 INCH IN 24 HOURS) IS ANTICIPATED FOR MUCH OF THE
FLORIDA PENINSULA AND PARTS OF THE SOUTHEAST AND MID-ATLANTIC COASTS SUN-THU.
FLOODING IS POSSIBLE FOR A SMALL PORTION OF WEST-CENTRAL FLORIDA. HIGH WINDS
(IN EXCESS OF 35 KNOTS) ARE EXPECTED FOR MUCH OF FLORIDA AND PARTS OF THE
SOUTHEAST AND MID-ATLANTIC COASTS SUN-THU. THE EXACT TRACK AND STRENGTH OF
ERIKA IS STILL HIGHLY UNCERTAIN AT THIS TIME. PLEASE CONSULT THE LATEST
ADVISORIES FROM NHC AT WWW.NHC.NOAA.GOV REGARDING THIS SYSTEM AND REFER TO
LOCAL NWS OFFICES FOR THE LATEST STATMENTS.



ANTECEDENT HEAVY RAINFALL LEADS TO POSSIBLE FLOODING FOR PARTS OF CENTRAL AND
EAST-CENTRAL IOWA.



LOW PRESSURE OVER THE GULF OF ALASKA IS EXPECTED TO CAUSE ONSHORE FLOW AND LEAD
TO HEAVY RAIN (IN EXCESS OF 2 INCHS IN 24 HOURS) FOR PARTS OF THE ALASKA
PANHANDLE SUNDAY. HEAVY RAIN IS ALSO POSSIBLE FOR EXTREME NORTHWESTERN
WASHINGTON STATE, BUT MODEL INCERTAINTY PRECLUDES THE SPECIFICATION OF A HAZARD
SHAPE AT THE CURRENT TIME.



MARGINAL CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE FOR PARTS OF THE CENTRAL
GREAT BASIN, NORTHERN INTERMOUNTAIN WEST, NORTHERN AND CENTRAL ROCKIES, AND
NORTHERN PLAINS SUNDAY. A HAZARD AREA IS NOT CURRENTLY SPECIFIED BUT ONGOING
FIRES ARE LEADING TO POOR AIR QUALITY FOR THE REGION.





THE TIGHT PRESSURE GRADIENT ASSOCIATED WITH AN AREA OF LOW PRESSURE OVER THE
GULF OF ALASKA AND HIGH PRESSURE OVER THE NORTHEAST PACIFIC/BERING SEA LEADS TO
HIGH WINDS (IN EXCESS OF 30 KNOTS) FOR PARTS OF THE ALASKAN PENINSULA, SOUTH
AND WESTERN COASTAL ALASKA, AND THE ALASKA PANHANDLE SUN-MON. SIGNIFICANT WAVES
ARE EXPECTED ACROSS NORTHERN PORTIONS OF THE SEWARD PENINSULA SUN.
NORTH-NORTHWESTERLY FLOW BEHIND THE AREA OF LOW PRESSURE FORECAST OVER THE GULF
OF ALASKA IS EXPECTED TO LEAD TO MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF
CENTRAL AND EASTERN ALASKA SUNDAY THROUGH WEDNESDAY.



TROPICAL ACTIVITY OVER THE EASTERN PACIFIC WILL NEED TO BE WATCHED AS SYSTEMS
MOVE WESTWARD TOWARD THE VICINITY OF HAWAII. HURRICANE IGNACIO, WHICH ON AUG 27
IS LOCATED NEAR 13N AND 139W, IS FORECAST TO MOVE NORTHWESTWARD TOWARD HAWAII.
BY AUG 31, HURRICANE IGNACIO IS FORECAST TO BE EAST OF HAWAII AND MOVE
NORTHWESTWARD FROM THERE. POSSIBLE IMPACTS ON HAWAII INCLUDE HEAVY RAIN, STRONG
WINDS, AND SIGIFICANT WAVES. PLEASE CONSULT THE LATEST ADVISORIES FROM NHC AT
WWW.NHC.NOAA.GOV REGARDING THE EVOLUTION OF THIS SYSTEM AND ITS INFLUENCE ON
THE HAWAIIAN ISLANDS.

FOR FRIDAY SEPTEMBER 04 - THURSDAY SEPTEMBER 10: AN UPPER-LEVLE RIDGE BUILDING
OVER THE CENTRAL AND EAST-CENTRAL CONUS LEADS TO A SLIGHT RISK OF MUCH ABOVE
NORMAL TEMPERATURES FOR PARTS OF THE CENTRAL/SOUTHERN GREAT PLAINS, LOWER AND
MIDDLE MISSISSIPPI VALLEYS, TENNESSEE AND OHIO VALLEYS, AND SOUTHEAST SEP 4-10,
AND A MODERATE RISK OF MUCH ABOVE NORMAL TEMPERATURES FOR PARTS OF THE SOUTHERN
PLAINS SEP 4.



AN UPPER-LEVEL RIDGE BUILDING OVER CENTRAL ALASKA AND DOWNSTREAM SURFACE
NORTHERLY FLOW LEADS TO A SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR
PARTS OF SOUTHEASTERN ALASKA SEP 4.



ACCORDING TO THE U.S. DROUGHT MONITOR MAP, VALID ON AUGUST 25, THE COVERAGE OF
SEVERE TO EXCEPTIONAL DROUGHT (D2 TO D4) DECREASED FROM 18.21 TO 18.07 PERCENT
ACROSS THE CONTIGUOUS U.S. SINCE THE PREVIOUS WEEK.

FORECASTER: RANDY SCHECHTER

$$




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.