Severe Thunderstorm Warning 30, NWS Marquette, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
400 PM EDT THU JUN 13 2002

COOL AND UNSETTLED WX PATTERN IN STORE FOR THE UPPER PENINSULA INTO
EARLY NEXT WEEK. MAIN FORECAST ISSUES WILL BE TEMPS AND PCPN
CHANCES...INCLUDING MENTIONS OF THUNDER. MODELS CONTINUE TO SHOW
SLOWER MOVING SYSTEM OVER THIS PERIOD...SO FORECAST WILL REFLECT
THIS.

UPPER LOW NOW SWIRLING OVER CENTRAL MN AND MOVING SLOWLY SEWD. SFC
TROF EXTENDING FROM UNDER THE UPPER LOW TO THE LOWER OHIO VALLEY.
COOL AIR ALOFT COMBINED WITH SHORTWAVE ENERGY PUSHING INTO WEST
CENTRAL WI RESPONSIBLE FOR TS DEVELOPMENT FROM WRN WI TO EXTREME WRN
U.P. A FEW SHRA/TS HAVE DEVELOPED IN CENTRAL AND EAST PARTS DUE TO
DIURNAL HEATING...TEMPS FROM KIMT TO KERY 70-75F BY 14Z.

AS UPPER LOW DROPS SEWD...EXPECT PCPN COVERAGE TO INCREASE THRU THE
EVENING. WITH SPEED MAX AND CAPE VALUES NR 1000 J/KG...WILL KEEP
MENTION OF TS GOING THROUGH EVENING IN ALL ZONES. FOCUS OF THE
CONVECTION WILL BE WEST AND SOUTH...BUT CANNOT RULE OUT TS
ELSEWHERE...ESPECIALLY CONSIDERING CURRENT SATELLITE PIX. 850-500MB
Q-VECTOR CONVERGENCE...UPPER DIFFLUENCE AND ISENTROPIC LIFT MOST
IMPRESSIVE EAST HALF TONIGHT. PWATS ABOVE .75 INCHES AS WELL. SHOULD
SEE WIDESPREAD RAIN TAKING SHAPE EAST...WITH NUMEROUS SHRA BECOMING
LESS SO WEST OVERNIGHT.

UPPER FORCING W/ CYCLONIC LOW LEVEL FLOW CONTINUES THROUGH FRIDAY
EASTERN ZONES AS SFC LOW DEEPENS OVER THE EASTERN LAKES. WILL KEEP
CATEGORICAL POPS GOING EAST AND SCT POPS WEST AS DRIER ADVECTS INTO
THE AREA. COOL AIR ALOFT WILL AID IN SHRA/TS DURING AFTERNOON IN THE
WEST. ONCE AGAIN...THIS SLOWER MODEL TREND BECOMING MORE CONVINCING
WITH EACH RUN.

FRIDAY NIGHT...LIKELY POPS CONTINUE IN THE EAST WITH PERSISTENT
UPPER DIFFLUENCE...Q-VECTOR CONVERGENCE AND PWATS EXCEEDING .75
INCHES. SFC LOW DEEPENS FURTHER AS SYSTEM BECOMES VERTICALLY
STACKED. SHORTWAVE RIDGING IN WEST (LESS APPARENT ON NEWEST MODEL
RUNS) WITH DRIER AIR SHOULD HELP TO END PCPN FOR A SHORT TIME THERE.

ON SATURDAY...CONTINUED COOL AIR ALOFT (H5 TEMPS NR -20C) WILL KICK
OFF DIURNAL SHOWERS...AND WILL INCLUDE FEW TS AS K-INDICES AND LAPSE
RATES WOULD SUGGEST. SFC GRADIENT TIGHTENS FURTHER FOR A BRISK N/NW
WIND OFF OF LAKE SUPERIOR. THIS WHILE 1000-500MB THICKNESSES DROP TO
549DM. UPPER AND SFC LOWS PERSIST OVER THE EASTERN LAKES. WHAT
HAPPENED TO SUMMER?

WILL KEEP SHOWERS AND FEW AFTERNOON TS GOING FOR SUNDAY AS LONGWAVE
TROUGH CONTINUES...AND COOL AIR ALOFT IS ACTUALLY REINFORCED BY
TROUGH CURRENTLY NEAR GREAT SLAVE LAKE. H5 TEMPS AGAIN DOWN TO -20C
OR SO.

IN THE EXTENDED...SHRA PERSIST INTO MONDAY...BUT WILL NOT MENTION TS
AS AIRMASS NOT QUITE AS UNSTABLE. MODELS AND ENSEMBLES AGREE IN
FINALLY EXITING THE UPPER LOW TUESDAY FOR A DRY DAY. SFC HIGH BUILDS
AND TEMPS SHOULD BE A LITTLE WARMER...BUT WILL LIKELY BE LAKE
BREEZES AS GRADIENT IS NON-EXISTENT. WAA ADVECTION WITH INCREASING S
WIND ON WEDNESDAY WILL PUSH TEMPS BACK ABOVE OR NEAR NORMAL...EXCEPT
THE NORTHERN LAKE MICHIGAN COAST. SHORT REPRIEVE ENDS THURSDAY AS
NEXT PACIFIC TROUGH BRINGS CHANCE OF SHRA/TS...THOUGH WITH ZONAL
FLOW TEMPS SHOULD BE NEAR SEASONAL INTO END OF THE WEEK.

COORDINATED WITH APX...THANKS.

.MQT...NONE.

JKL

MIZ006>007-011>014-132200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MARQUETTE MI
1220 PM EDT THU JUN 13 2002

...HAZARDOUS WEATHER POTENTIAL STATEMENT FOR WEST AND CENTRAL UPPER
MICHIGAN...

AS AN UPPER LEVEL LOW PRESSURE SYSTEM OVER MINNESOTA DRIFTS SLOWLY
TOWARD UPPER MICHIGAN...SCATTERED SHOWERS WILL CONTINUE TO DEVELOP
ACROSS WEST AND CENTRAL UPPER MICHIGAN. ISOLATED THUNDERSTORMS ARE
ALSO POSSIBLE...MAINLY WEST OF A LINE FROM MARQUETTE TO MENOMINEE.
BETWEEN 3 PM AND 9 PM...SOME OF THE STRONGER STORMS SOUTH OF A LINE
FROM ONTONAGON TO POWERS MAY PRODUCE HAIL UP TO THREE-QUARTERS OF
AN INCH.

ANY THUNDERSTORMS THAT DEVELOP WILL MOVE NORTHEAST AT 20 MPH. ALL
THUNDERSTORMS PRODUCE DEADLY LIGHTNING.

STAY TUNED TO NOAA WEATHER RADIO OR YOUR FAVORITE MEDIA SOURCE FOR
THE LATEST WEATHER INFORMATION.

JLB