Prognostic Meteorological Discussion
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FXUS21 KWNC 222007
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT AUGUST 22 2014

SYNOPSIS: A STATIONARY FRONT IS PREDICTED TO STRETCH FROM THE GREAT LAKES TO
THE FOUR CORNERS REGION FOR MUCH OF THE FIRST HALF OF THIS PERIOD. UPSTREAM A
COLD FRONT IS EXPECTED TO ENTER THE PACIFIC NORTHWEST BY LATE NEXT WEEK. SOUTH
OF THIS FRONT, TEMPERATURES ARE FORECAST TO BE ABOVE NORMAL WITH DAILY HIGHS
WELL INTO THE 90S. MEANWHILE, AREAS BEHIND THIS FRONT ACROSS THE NORTHERN
PLAINS ARE EXPECTED TO EXPERIENCE COOLER, BELOW-NORMAL TEMPERATURES.

HAZARDS

HEAVY RAIN FOR PARTS OF THE MIDDLE AND UPPER MISSISSIPPI VALLEY, CENTRAL
PLAINS, AND GREAT LAKES, MON-WED, AUG 25-27.

MUCH ABOVE NORMAL TEMPERATURES FOR PARTS OF THE CENTRAL AND SOUTHERN PLAINS,
MON-TUE, AUG 25-26.

EXCESSIVE HEAT FOR PARTS OF THE MIDDLE AND LOWER MISSISSIPPI, OHIO, AND
TENNESSEE VALLEYS, MON-TUE, AUG 25-26.

MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF THE NORTHERN ROCKIES, SAT-MON, AUG
30-SEP 1.

SEVERE DROUGHT FOR THE CENTRAL AND SOUTHERN GREAT PLAINS, SOUTHWEST, PACIFIC
NORTHWEST, GREAT BASIN, AND CALIFORNIA.

DETAILED SUMMARY

FOR MONDAY AUGUST 25 - FRIDAY AUGUST 29: AN UPPER-LEVEL SHORTWAVE IS FORECAST
TO PROPAGATE ACROSS THE WESTERN TWO-THIRDS OF THE CONUS DURING WEEK-1. THE
ASSOCIATED STATIONARY FRONT AHEAD OF THIS SHORTWAVE IS EXPECTED TO BRING HEAVY
RAIN TO PARTS OF THE MIDDLE AND UPPER MISSISSIPPI VALLEY, CENTRAL PLAINS, AND
GREAT LAKES MONDAY TO WEDNESDAY. SOME MODELS INDICATE THE POTENTIAL FOR SOME
AREAS TO RECEIVE BETWEEN 2 AND 3.5 INCHES IN A 24-HOUR PERIOD, WITH THE
GREATEST AMOUNTS EXPECTED OVER NEBRASKA AND IOWA.



AN UPPER-LEVEL RIDGE IS PREDICTED TO DOMINATE OVER SOUTH-CENTRAL AND
SOUTHEASTERN CONUS EARLY IN THE PERIOD. THIS PATTERN IS EXPECTED TO SUPPORT
MUCH ABOVE NORMAL TEMPERATURES ACROSS PARTS OF THE CENTRAL AND SOUTHERN PLAINS
MONDAY TO TUESDAY. DAILY MAXIMUM TEMPERATURES IN PARTS OF THIS AREA ARE
ANTICIPATED TO BE 12 DEGREES F ABOVE NORMAL. PARTS OF THE MIDDLE AND LOWER
MISSISSIPPI, OHIO, AND TENNESSEE VALLEYS HAVE AN ELEVATED RISK OF EXCESSIVE
HEAT MONDAY TO TUESDAY. PARTS OF THESE AREAS MAY EXPERIENCE DAILY MAXIMUM HEAT
INDEX TEMPERATURES OF 105 TO 110 DEGREES F, WITH THE HIGHEST HEAT INDEX
TEMPERATURES EXPECTED FOR LOWER LOUISIANA, POTENTIALLY REACHING 110 TO 115 F.



THE TROPICAL EASTERN PACIFIC IS PREDICTED TO REMAIN VERY ACTIVE DURING THIS
PERIOD WITH THREE DISTURBANCES CURRENTLY IDENTIFIED AS OF AUGUST 22, 7:37AM
PDT. TROPICAL STORM KARINA IS THE FURTHEST WEST OF THESE CYCLONES. TROPICAL
STORM LOWELL IS LOCATED NORTHEAST OF KARINA AND EXPECTED TO IMPACT KARINA`S
PATH. THE CURRENT TROPICAL STORMS ARE CURRENTLY FORECAST TO REMAIN WELL OUT TO
SEA AND NOT AFFECT LAND.



IN THE TROPICAL ATLANTIC, AS OF 2PM EDT ON FRIDAY AUGUST 22, THE NATIONAL
HURRICANE CENTER (NHC) IS PREDICTING A 70% CHANCE OF A CURRENT DISTURBANCE
FORMING INTO A TROPICAL SYSTEM DURING THE NEXT FIVE DAYS. IN GENERAL, THE
MAJORITY OF TODAY`S NUMERICAL MODELS HAVE TAKEN THIS FEATURE FURTHER EAST
OFFSHORE THAN IN YESTERDAY`S RUNS, PRECLUDING ANY ASSOCIATED HAZARDS FROM BEING
IDENTIFIED AT THIS TIME. UPDATED CONDITIONS AND FORECASTS SHOULD BE MONITORED
USING NHC`S WEBPAGE AT HTTP://WWW.NHC.NOAA.GOV.

FOR SATURDAY AUGUST 30 - FRIDAY SEPTEMBER 05: THE 06Z DETERMINISTIC GFS AND
GEFS MEAN INDICATES THE POSSIBILITY OF SURFACE LOW PRESSURE EXTENDING FROM
CENTRAL CANADA INTO THE GREAT PLAINS DURING THE FIRST HALF OF THE WEEK-2
PERIOD. THIS PATTERN MAY SUPPORT MUCH BELOW NORMAL DAILY MINIMUM TEMPERATURES
ACROSS PARTS OF THE NORTHERN ROCKIES NEXT SATURDAY TO THE FOLLOWING MONDAY. THE
GEFS REFORECAST TOOL INDICATES A 20% CHANCE OF THIS AREA EXPERIENCING DAILY
MINIMUM TEMPERATURES BELOW THE LOWER 15TH PERCENTILE AND UP TO A 60% CHANCE OF
SUBFREEZING TEMPERATURES, WITH THE ROCKIES IN WYOMING HAVING THE GREATEST
LIKELIHOOD.



THE MOST RECENT U.S. DROUGHT MONITOR, RELEASED ON AUGUST 21, SHOWS THE
PERCENTAGE OF CONUS IN SEVERE DROUGHT DECREASING VERY SLIGHTLY FROM 22.03% TO
21.62%.

FORECASTER: MELISSA OU

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