Severe Thunderstorm Warning 48, NWS Gaylord, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
320 AM EDT THU JUN 13 1996

06Z SFC ANAL SHOWS MAIN TROF/FNT POSITION WORKING THROUGH WRN UPR SWWRD
TO THE SOUTHEAST TIP OF MN. THIS PLACEMENT IS A BIT FASTER THAN CURRENT
NGM/ETA PROGS...IN WHICH NGM HAS FNT EXTENDING FRM CEN UPR THROUGH THE
MN/IA/WI INTERSECTION BY 12Z. LATEST ADAP SSW MAP SHOWS BEST STREAMLINE
CONVERGENCE IN NRN SECTIONS ALONG THE FNT...BASICALLY IN WRN/CEN UPR
MI. THIS ALSO IS WHERE BEST SFC MOIST CONVRGENCE IS LOCATED ATTM. AS A
RESULT...MAIN AREA OF SCT SHOWERS (AND THERE AREN/T MANY) SHOW UP ON
KGRB 88D NW OF IMT...NW AND W OF GRB. SHOWERS NOT VERY EXTENSIVE GIVEN
LACK OF UPR LVL SUPPORT. MAIN VORT MAX/TROFFING IN 500 HGHT FIELDS ARE
MOVING E OF FA AND AHEAD OF SFC CNVRGNC/TROF. MAIN FCST PROB WILL BE
THE SHORT TERM...CHC/S OF PCPN FOR FA THIS MORNING.

48 HR TERM MODELS IN EXLNT AGREEMENT...LOOKED PRIMARILY AT NGM. BEST
CHC/S OF PCPN WILL MOVE FRM W TO E ACROSS FA THIS MORNING. GIVEN FASTER
MOVEMNT OF FNT (COMPARED TO PROGS)...WOULD EXPECT BEST CHCS OF RW
DURING THE MORNING HOURS W/DECRS CLOUDS THIS AFT. ERN UPR ALREADY SEEING
SOME SCT RW ACCORDING TO LATEST KAPX 88D LOOP OF BASE REFL. TIMING OF
PCPN INTO NE LWR STILL LOOKS LIKE MAINLY LATE MORNING INTO LATE AFT.
AGAIN...NOT MUCH UPR LVL SUPPORT WITH THIS AREA...THEREFORE WOULD KEEP
POPS IN THE 30 TO 40 PCT RANGE. AS FOR THUNDER...MODIFIED KAPX SOUNDING
FOR SFC TEMPS IN LOW 70S (LATE MORNING) WITH DEWPTS IN LOW 60S...ALSO
TAYLORED UPR LVL TEMPS TO UPSREAM READINGS (WHICH ARE SLIGHTLY HIGHER
THAN 00Z READINGS AS THCK TROF EXITS THE FA). CAME UP W/ LI/S OF -2 TO
-4 WITH MRGNL CAPE BETW 700-900 J/KG. BELIEVE THERE COULD BE SOME
THUNDER WITH THIS AREA OF PCPN AS IT REACHED FA...BUT ALSO FEEL BEST
CHCS WILL BE IN NE LWR WHERE SS (LOW LVL INSTAB) WILL BE GREATER IN
ADDITION TO THIS AREA BEING A BIT MORE INTO EXITING UPR LVL TROF
(SLIGHTLY COOLER TEMPS ALFT).

AS FOR REST OF PERIOD...DRY PATTERN SHAPES UP ACROSS FA STARTING THIS
AFT NW LWR/ERN UPR AND LATE THIS AFT NE LWR. CLEARING SKIES OVERNIGHT
WITH SUNNY CONDITIONS EXPECTED ON FRI WITH NVA/RIDGING ALFT AND SFC
HIGH PUSHING INTO REGION. WOULD LOOK FOR MAINLY CLEAR CONDITIONS TO
CONTINUE INTO SAT...WITH ANOTHER TROF WORKING INTO NW PLAINS BRINGING A
RETURN SRLY FLOW INTO THAT REGION...STILL W OF MI.

MOS TEMPS LOOK GOOD W/ PERHAPS EXCEPTION OF HIGH TEMPS ON FRI (TAD
HIGH) GIVEN SLIGHT CAA. OF COURSE...A NW WIND FRI WILL KEEP COASTAL LK
MI/ERN LK SUPERIOR AREAS COOLER AS WELL. WK SFC GRADIENT SAT COULD ONCE
AGAIN LEAD TO COOLER TEMPS ALONG ALL COASTLINES AS ONSHORE WINDS DVLP.

APN TU 081/055 078/048 073 XX400
TVC WU 080/057 078/052 077 XX400
GLD WU 080/055 079/050 075 XX400
HTL WU 080/053 079/051 076 XX400
SSM WU 076/049 076/044 071 XX500

HURLEY