Severe Thunderstorm Warning 22, NWS Marquette, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
335 PM EDT SAT JUN 10 2000

FCST CONCERN IS CONVECTION THIS EVNG AND LATER TONIGHT

H5 PATTERN FEATURES A DEAMPLIFYING TROF OVR WRN CONUS WITH RIDGE OVR
CNTRL CONUS. SHRTWV OVR ERN DAKOTAS DIGGING INTO WRN MN PER 12Z
ROABS/WV IMG. H85 FNT ARCS FM H85 LOW OVR ND/MN BORDER TO JUST NORTH
OF LK SUPERIOR SE INTO LK ONTARIO. SFC LOW IS STATIONED OVR BJI MN
GRADUALLY SLIDING E-NE. SFC WM FNT STRETCHES FM LOW OVR NRN UPR MI
DOWN INTO LK HURON. SFC DWPTS AOA 65F ARE POOLING ALONG FNTAL
BOUNDARY WITH DWPT POOL AOA 70 KNOCKING ON UPR MI/S DOOR MAKING IT
ALL THE WAY UP TO EGV WI AS OF 16Z. 88D SHOWING NARROW PERSISTANT
LINE OF CONVEX THAT DEVELOPED OVR WRN LK SUPERIOR AROUND 16Z NOW
MOVING INTO CNTRAL UPR MI ATTM. WITH FREEZING LEVEL AROUND 14K FT
AND MOIST ATMOS COLUMN THROUGH H5 PER RAOBS/WV IMG...MAIN THREAT HAS
BEEN BRIEF HVY RAINS (IWD PICKED UP .47 INCH IN HALF HOUR)

TONIGHT...WITH FRNTAL BOUNDARY TO NORTH UPR MI FINDS ITSELF IN WARM
SECTOR OF NRN PLAINS SYSTEM. HOWEVER...AS MID LEVELS ARE STILL
FAIRLY WARM (H85 TEMPS 18-20C/H7 TEMPS 9-10 PER 12Z ROABS) AND WITH
NO APPRECIABLE CAA OCCURRING ALOFT LIMITING DIFFERENTIAL TEMP
ADVECTION...EXPECT SVR THREAT TO BE LIMITED THIS AFTN. BETTER SHOT
OF SVR WX APPEARS TONIGHT AS INSTABILITY PARAMETERS (LI/S AOB
-4...SFC CAPES 2K-2.5K J/KG...TT AOA 40) AND SLTLY BETTER DYNAMICS
W/ MN SHRTWV LOBE PRESSING THROUGH (BETTER DEFINED H7 SHRTWV)
COMBINED WITH INCREASING LLJ (40KT) AND UPR MI STATIONED IN THE RRQ
OF THE H3 JET (ALBEIT WEAK) EXITING THE NRN PLAINS BY 06Z. 12Z
MESOETA DEVELOPS CONVEX OVR NCNTRL UPR MI BY 03Z AS H3 DIVERGENCE/H7
OMEGA BULLSEYE APPEAR AT THIS TIME. WITH H5 RIDGE OVRHEAD AND H7
SHRTWV TO WEST ALONG WITH H85 DWPTS RISING INTO THE UPR TEENS AND H7
RH AOA 70 PERCENT THIS APPEARS TO BE A LIKELY SCENARIO. WITH H7 RH
DECREASING RAPIDLY BTWN 06Z-12Z PER MESOETA AND FZG LEVEL FALLING
SLIGHTLY OVRNIGHT HAIL COULD BECOME A THREAT FM THE CONVECTION.

SUNDAY/MONDAY...DESPITE H8-H5 Q-VECTOR DIVERGENCE BEHIND H5 SHRTWVS
PASSING...BELIEVE AT LEAST FIRST PART OF DAY WL BE PRETTY GRUNGY.
MAIN FACTOR FOR DREARY DAY WL BE H925-H95 MOISTURE STICKING AROUND
AFTER OVRNIGHT RAIN W/ UPSLOPE COMPONENT ALONG LK SUPERIOR BRINGING
FOG BACK TO HIGHER ELEVATIONS. WITH NRLY WIND VS. EAST DON/T BELIEVE
FOG WL GET OUT OF HAND ACROSS KEWEENAW PENINSULA AS WAS THE CASE
OVRNIGHT LAST NIGHT. CLOUDS SHOULD BEGIN TO LIFT SLOWLY LATE IN THE
DAY PER 12Z MESOETA RH FIELDS/TIME SECTIONS. MONDAY HAVE ELECTED TO
REMOVE POPS FM PREV FCST AS MODELS DONT BRING DEEP MOISTURE AND
PRECIP INTO UPR MI UNTIL AFTER 00Z.

IN THE EXTENDED...ALL MEDIUM RANGE MODELS IN GOOD AGREEMENT THAT H5
TROF OVR WRN CONUS WL SLIDE EAST ACROSS COUNTRY. WITH TROF CENTERED
OVR UPR MS VALLEY BY 12Z WED PER MRF/ECMWF/UKMET/CAN/ENSEMBLES TUE
INTO WED APPEARS TO BE BEST SHOT AT WIDESPREAD RAIN AS FAIRLY STRONG
LOW IS PROGGED TO FORM IN FRNT OF TROF. AS HTS BEGIN TO BUILD SLGTLY
EXPECT PRECIP CHANCES TO DIMINISH BY LATE WEEK. HOWEVER WITH THIS
TRANSITION EXPECTED TO BE SLOW IN LIGHT OF STRNG WRN H5 RIDGE EXPECT
CLOUDS TO CONTINUE TO HANG IN. WITH H85 TEMPS IN THE LOW TEENS PER
MRF/ECMWF TEMPS GENERALLY IN THE 60S WL BE THE EXPECTATION...AT OR
SLGTLY BLO NORMAL.

.MQT...NONE.

JLA

MIZ001>007-009>014-111200-

SEVERE WEATHER POTENTIAL STATEMENT
NATIONAL WEATHER SERVICE MARQUETTE MI
1150 AM EDT SAT JUN 10 2000

...SEVERE WEATHER OUTLOOK FOR WEST AND CENTRAL UPPER MICHIGAN...

SHOWERS AND THUNDERSTORMS ARE LIKELY OVER CENTRAL AND WESTERN UPPER
MICHIGAN THIS AFTERNOON AND TONIGHT. THERE IS A SLIGHT RISK OF
SEVERE THUNDERSTORMS OVER WESTERN AND CENTRAL UPPER MICHIGAN THIS
AFTERNOON AND TONIGHT.

LOW PRESSURE MOVING THROUGH THE UPPER MIDWEST WILL MOVE EAST
APPROACHING UPPER MICHIGAN THIS EVENING. AHEAD OF IT...SHOWERS AND
THUNDERSTORMS WILL DEVELOP THIS AFTERNOON. THUNDERSTORMS ARE
EXPECTED AFTER 2 PM EDT IN IRONWOOD...AFTER 4 PM IN MARQUETTE AND
IRON MOUNTAIN...AND AFTER 6 PM IN MUNISING AND NEWBERRY. ANY STORMS
THAT DEVELOP THIS AFTERNOON WILL BE CAPABLE OF PRODUCING HAIL TO 1
INCH IN DIAMETER...VERY HEAVY RAIN...AND WIND GUSTS TO 60 MPH. THE
STORMS WILL MOVE NORTHEAST AT 25 MPH.

THUNDERSTORMS MAY REDEVELOP TONIGHT AFTER 8 PM EDT OVER CENTRAL AND
UPPER MICHIGAN. SOME OF THESE STORMS MAY ALSO BE SEVERE. THE MAIN
THREAT BEING HAIL TO 1 INCH IN DIAMETER AND WIND GUSTS TO 60 MPH. THE
STORMS WILL MOVE EAST AT 25 MPH.

TUNE INTO NOAA WEATHER RADIO...OR LOCAL TELEVISION OR RADIO STATIONS
FOR THE LATEST WEATHER INFORMATION.

ALTOE