Severe Thunderstorm Warning 38, NWS Gaylord, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
419 PM EDT SUN JUL 22 2001

SYNOPSIS/MODELS...SFC RETURN FLOW HAS TURNED MORE TO THE SOUTHWEST
TODAY WITH THE SFC LOW AND FRONT OFF TO THE WEST IN THE CENTRAL
PLAINS STATES. MCS THAT FORMED IN SOUTH DAKOTA LAST EVENING IS
WEAKENING IN WEST CENTRAL WISCONSIN THIS AFTERNOON. WHILE IT IS
BEGINNING TO TURN SOUTHEAST WILL BE CONCERNED WITH DEBRIS CLOUDINESS
AND POSSIBLE PRECIPITATION IN THE SW PORTION OF THE CWFA. THE OTHER
CONCERN OF THE PACKAGE WILL BE WITH THE FRONT PASSAGE ON MONDAY.
MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE TIMING OF THE FRONT AND
THE MAJOR FEATURES OF THE PACKAGE.

TONIGHT...THE AFTERNOON CONVECTION WILL BEGIN TO DIE DOWN DURING THE
EVENING AS THE SUN SETS. AREAS OF FOG WILL AGAIN BE A PROBLEM WITH
THE DEWPOINTS REMAIN IN THE UPPER 60S AND THE LOWER 70S. THE MODELS
SUGGEST THAT THE NOCTURNAL CONVECTION WILL REMAIN SOUTHWEST OF THE
STATE WITH THE LLJ (850 MB 25KT) NEBRASKA INITIALIZING THE
CONVECTION THEN CONTINUING INTO IOWA. SO HAVE REMOVED THE
THUNDERSTORMS FOR THE AFTER MIDNIGHT TIME FRAME.

MONDAY...CONVECTION WILL BEGIN TO FIRE ALONG THE SFC TROUGH IN THE
CENTRAL PLAINS AS IT MOVES INTO WISCONSIN OVERNIGHT. AN AREA OF
700-300MB DPVA IS ALSO MOVING ALONG WITH THIS FEATURE. THE TIMING OF
THE THUNDERSTORMS LOOKS LIKE LATE MORNING IN THE WEST AND THE EARLY
AFTERNOON IN THE EAST.

MONDAY NIGHT/TUESDAY...SFC TROUGH WILL PASS THROUGH THE REGION
DURING THE EVENING. 700-500 MB RH DROPS TO LESS THAN 20% WITH 850 RH
BEGINNING TO DECREASE AS WELL, BUT STAYS ABOVE 50% LONG ENOUGH INTO
THE DAY THAT PARTLY CLOUDY OVERNIGHT AND PARTLY SUNNY DURING THE
DAY. AS THE SFC HIGH BUILDS, THE 500 TROUGH SLIDES OFF TO THE EAST
WITH THE RESULTING SUBSIDENCE SUPPRESSING ANY SHOWER ACTIVITY.

TUESDAY NIGHT...EXPECT THE SKY TO CLEAR OUT AS THE 850 RH DROPS TO
20% AND THE 700-500 RH IS AROUND 15%.

EXTENDED...ENSEMBLE MODELS OF THE GEM AND MRF ARE IN GOOD AGREEMENT.
AT 500 MB IN THE LATER PERIODS THE MRF OPERATIONAL MODEL LOOKS A BIT
LIKE IT IS THE OUTLIER WITH MOST OF THE ENSEMBLE MEMBERS IN A MORE
ZONAL PATTERN BY DAY 6 AND 7. THE CANADIAN ENSEMBLE AND OPERATIONAL
MODELS SUPPORT THIS. THE MRF AND ECMWF ARE IN GOOD AGREEMENT THROUGH
DAY 6 WITH THE SFC PATTERN THOUGH AND THE RUN TO RUN CONSISTENCY
LOOKS GOOD AT THE SFC WHEN COMPARED WITH YESTERDAY'S HPC FORECAST.
SO THE FORECAST LOOKS LIKE THIS...WEDNESDAY THROUGH SATURDAY WILL
REMAIN IN THE DRY CATEGORY WITH THE SFC HIGH PARKED OVER THE GREAT
LAKES. SUNDAY WILL HAVE A CHANCE OF SHOWERS AND THUNDERSTORMS WITH
THE SYSTEM FROM THE PLAINS APPROACHING THE REGION. THE MRF SUGGESTS
THAT IT WILL BE SUNDAY NIGHT, BUT WITH IT BEING DAY 7 THE TIMING
WILL PROBABLY CHANGE OVER THE NEXT FEW DAYS.

BELOW ARE THE RECORDS FOR MONDAY.

7/23 RECORD HIGHS: APN 93/1987...HTL 95/1940...TVC 97/1940.

.APX...NONE.

LUTZ