Severe Thunderstorm Warning 27, NWS Gaylord, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
446 PM EDT WED JUN 14 2000

SYNOPSIS OVER THE GREAT LAKES...SFC LOW ALONG MN/ONTARIO BORDER WITH
A COLD FRONT EXTENDING INTO THE S MS VALLEY. H5 MAX IN S MN IS
MOVING E.

MODELS ARE IN FAIR AGREEMENT THROUGH 60HRS, EXCEPT FOR THE EVOLUTION
OF THE SFC FEATURES FROM 42 THROUGH 54 HOURS. THIS WILL AFFECT THE
SPEED OF THE FRONT ON FRIDAY. ETA SUGGESTS THAT THE FORCING IS
THROUGH THE CWFA BY 00Z SAT WHILE THE AVIATION IS ABOUT 6 HOURS
SLOWER. AS FAR AS INITIALIZATION, THE MODELS LOOK PRETTY GOOD WITH
THE H5 MAX MOVING THROUGH S MINNESOTA.

TONIGHT...EXPECT SHOWERS AND THUNDERSTORMS TO BE LIKELY ACROSS THE
AREA AS DEWPOINTS ARE IN THE LOWER TO MID 60S, CAPES IN THE 500-1000
J/KG AND SFC LI'S TO AROUND -5 ON THE 18Z MESOETA. THE QUESTION IS
WHETHER THE CURRENT STORMS IN SOUTHERN LOWER BRING RAIN INTO THE
AREA FIRST HELPING TO STABILIZE THE AIR IN NORTHERN LOWER. WE WOULD
STILL GET THUNDERSTORMS, BUT MORE WITH HEAVY RAIN WITH PWAT >1.5".
H5 VORT MAX WILL BE MOVING INTO THE CWFA OVERNIGHT WITH THE COLD
FRONT STILL TO THE WEST. HOWEVER, A FEW SEVERE THUNDERSTORMS MAY BE
POSSIBLE IN THE SOUTHERN PARTS OF THE CWFA.

THURSDAY...WITH THE COLD FRONT THROUGH THE REGION AND THE UPPER
TROUGH AXIS JUST TO THE WEST EXPECT SHOWERS MAINLY IN THE MORNING IN
NORTHERN LOWER. EASTERN UPPER WILL STILL BE IN AN AREA OF DPVA WITH
850-500 MB LAYER RH STILL >60%. NORTHERN LOWER MAY GET AN AFTERNOON
SHOWERS BUT THE MOISTURE IS CLOSER TO 50% IN THE 850-500 LAYER AND
WITH ALIGNED FLOW FROM THE SFC TO AROUND 500 MB EXPECT THINGS TO BE
WELL MIXED WITH PARTLY SUNNY SKY. IT WILL BE BREEZY AS WELL DUE TO
THE ALIGNED FLOW AS WELL.

THURSDAY NIGHT/FRIDAY...WILL SEE A SECOND ROUND OF SHOWERS AND
THUNDERSTORMS STARTING IN THE WEST IN THE EVENING DUE TO ANOTHER H5
MAX MOVING IN FROM THE NORTHERN PLAINS AND DEEP MOISTURE (SFC-500).
A SECOND COLD FRONT WILL APPROACH WITH THE SFC LOW PRESSURE COMING
OUT OF NORTHERN MINNESOTA. CAPES WILL BE AROUND 200-400 J/KG MAINLY
IN THE SOUTHERN PARTS OF THE CWA. BY 12Z FRI WE ARE IN THE RRQ OF
THE 300MB WITH A 23 MAX AT H5 MOVING OVER KTVC. MOST OF THE ACTION
WILL BE NORTH OF A KAPN-KHTL LINE.

FRIDAY NIGHT...THE COLD FRONT PASSES THROUGH THE AREA THIS WILL MAKE
THE RAIN MORE LIKELY IN THE SE PART OF THE CWFA WHILE THE REST OF
THE CWFA WILL SEE THE RAIN BEGINNING TO END.

EXTENDED...MRF AND CANADIAN MEANS ARE IN FAIR AGREEMENT THROUGH THE
7 DAY PERIOD WITH THE H5 FLOW TURNING ZONAL AROUND DAY 4 OR 5. THE
MRF SPAGHETTI PLOTS WERE SCATTERED ABOUT MORE THAN THE CANADIAN. OF
THE FOUR MODELS THE CANADIAN AND ECMWF WERE CLOSER TOGETHER WITH
NOGAPS AND MRF CLOSER OUT THROUGH 108 HOURS. HOWEVER, THE
DIFFERENCES IN THE FOUR MODELS AREN'T MAJOR. SO THE FORECAST WILL
HAVE FEW CHANGES. SATURDAY...AS THE SFC LOW PULLS OUT SATURDAY
MORNING FROM EASTERN UPPER WILL KEEP THE SHOWERS IN THERE AND ALLOW
NORTHERN LOWER TO BE DRY. SUNDAY AND MONDAY WILL BOTH BE DRY AS SFC
RIDGE DOMINATES THE AREA. MONDAY ON THE MRF SHOW THE H5 TROUGH AXIS
MOVING THROUGH WHERE THE ECMWF IS ZONAL. WITH THE ZONAL PATTERN
SETTING UP OVER THE AREA WILL LEAVE ANY PRECIP OUT OF THE LONG RANGE
FOR NOW. TUESDAY WILL LEAVE IN THE CHANCE OF PRECIPITATION THE MRF
HAS BACKED OFF ON THE CHANCE AND THE ECMWF HAS A SIMILAR LOOK. WILL
WAIT ANOTHER RUN TO SE<E IF THE PRECIPITATION SHOULD BE PULLED OUT OF
THE LONG RANGE HERE. WEDNESDAY, THE MRF BRINGS THE LOW IN FROM THE
WEST BOTH AT THE SFC AND AT H5. SO HAVE PUT IN THE CHANCE FOR
PRECIPITATION.

.APX...NONE.

LUTZ