Prognostic Meteorological Discussion
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2
000
FXUS21 KWNC 291948
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT AUGUST 29 2014

SYNOPSIS: A COLD FRONT IS FORECAST TO MOVE ACROSS THE NORTHERN TIER OF THE
LOWER 48 DURING THE FIRST HALF OF NEXT WEEK. HIGH PRESSURE IS PREDICTED OVER
THE SOUTHEAST AND MUCH OF THE SOUTHERN GREAT PLAINS DURING NEXT WEEK. LATER
NEXT WEEK, AN UPPER-LEVEL SYSTEM IS FORECAST TO MOVE FROM THE PACIFIC NORTHWEST
TO THE NORTHERN GREAT PLAINS. A WEAK LOW-PRESSURE SYSTEM IS ANTICIPATED TO
IMPACT SOUTHERN ALASKA EARLY IN THE OUTLOOK PERIOD, FOLLOWED BY A RATHER
TRANQUIL PERIOD.

HAZARDS

HEAVY RAIN FROM THE CENTRAL GREAT PLAINS TO THE GREAT LAKES, MON-TUE, SEP 1-2.

HEAVY RAIN FOR SOUTHERN TEXAS, TUE-WED, SEP 2-3.

HEAVY RAIN FOR THE UPPER MIDWEST, THU, SEP 4.

HEAVY RAIN FROM THE NORTHERN AND CENTRAL GREAT PLAINS TO THE GREAT LAKES,
FRI-SAT, SEP 5-6.

FLOODING IN MONTANA, SOUTHWEST IOWA, AND NORTHWEST MISSOURI.

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

DETAILED SUMMARY

FOR MONDAY SEPTEMBER 01 - FRIDAY SEPTEMBER 05: A COLD FRONT IS LIKELY TO
TRAVERSE THE NORTHERN TIER OF THE LOWER 48. HEAVY RAINS (1-2 INCHES IN 24
HOURS) ARE FORECAST TO ACCOMPANY THE FRONT. THE HEAVIEST RAINS ARE LIKELY FROM
KANSAS TO INDIANA. ISOLATED SEVERE THUNDERSTORMS ARE ALSO POSSIBLE OVER THE
SAME REGION, BUT NO SPECIFIC SEVERE WEATHER THREAT AREA IS DESIGNATED AS THE
SPATIAL COVERAGE OF SEVERE WEATHER IS LIKELY TO BE SMALL.



THAT COLD FRONT IS LIKELY TO STALL ACROSS THE MIDDLE OF THE CONUS, YIELDING AN
INCREASED THREAT FOR HEAVY RAINS THROUGH NEXT WEEK ACROSS THE CENTRAL AND
NORTHERN GREAT PLAINS AND MIDWEST. THE MOST LIKELY DAYS ARE SEP 4, ACROSS THE
UPPER MIDWEST, FOLLOWED BY A LARGER AREA FROM THE PLAINS TO THE GREAT LAKES,
ASSOCIATED WITH A MORE VIGOROUS UPPER-LEVEL VORTICITY MAX DURING SEP 5-6.



A RIDGE IS LIKELY OVER THE SOUTHEAST, RESULTING IN SLIGHTLY HIGHER THAN NORMAL
TEMPERATURES. EASTERLY FLOW AND THE IMPACTS OF A TROPICAL EASTERLY WAVE ARE
LIKELY TO RESULT IN HEAVY RAINS ACROSS SOUTH TEXAS DURING THE MIDDLE OF NEXT
WEEK. THE NATIONAL HURRICANE CENTER HAS A 30% CHANCE OF DEVELOPMENT DURING THE
NEXT 5 DAYS ACROSS THE SOUTHERN GULF OF MEXICO.



THE ECMWF AND CANADIAN MODELS ALSO DEPICT HEAVY RAINS OVER FLORIDA ON SEP 5,
BUT UNCERTAINTY ABOUT LOCATION (BETWEEN THE ECMWF AND CANDIAN) AND TIMING (GFS
IS MUCH LATER, GEFS MEAN HAS NO SIGNAL) PRECLUDE THE DEPICTION OF A HAZARD AT
THIS TIME.



GIVEN THE RECENT HEAVY RAINS AND FORECAST RAINFALL ACROSS THE NORTHERN GREAT
PLAINS, FLOODING IS FORECAST TO CONTINUE ACROSS MONTANA. THE FORECAST RAINFALL
ACROSS THE CENTRAL GREAT PLAINS AND MIDWEST ARE LIKELY TO EXACERBATE FLOODING
IN THE MISSOURI RIVER BASIN DURING NEXT WEEK.



A WEAK LOW PRESSURE SYSTEM IS FORECAST NEAR THE ALASKA PANHANDLE. RAINFALL
TOTALS ARE LIKELY TO EXCEED 1 INCH IN 24 HOURS, BUT ONLY VERY LOCALIZED AREAS
ARE FORECAST TO RECEIVE 2 INCHES OR MORE IN 24 HOURS, SO NO HAZARD IS DEPICTED.




A TROUGH IS LIKELY TO MOVE ACROSS THE PACIFIC NORTHWEST DURING THE LATER
PORTIONS OF NEXT WEEK. SNOW LEVELS ARE LIKELY TO DROP TO NEAR 6500 FEET ACROSS
THE NORTHERN ROCKIES DURING FRIDAY.

FOR SATURDAY SEPTEMBER 06 - FRIDAY SEPTEMBER 12: BELOW NORMAL TEMPERATURES ARE
LIKELY ACROSS THE NORTHERN ROCKIES DURING THIS PORTION OF THE OUTLOOK. SLIGHTLY
ELEVATED ODDS OF MUCH BELOW NORMAL TEMPERATURES ARE INDICATED WHERE MODELS HAVE
ANOMALIES OF 8-12 DEGREES F BELOW NORMAL, AND THE ODDS OF BEING IN THE LOWEST
15TH PERCENTILE ARE MORE THAN 20%.



THE MOST RECENT U.S. DROUGHT MONITOR, RELEASED ON AUGUST 28, INDICATES THE
PERCENTAGE OF CONUS IN SEVERE TO EXCEPTIONAL DROUGHT DECREASING VERY SLIGHTLY
TO 21.55 PERCENT.

FORECASTER: MATTHEW ROSENCRANS

$$



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