Hail and Damaging Winds in Michigan, May 14, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1228 PM EDT MON MAY 14 2007

.UPDATE...

...SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON INTO THIS EVENING...

THUNDERSTORM FORMATION STILL FAVORABLE THIS AFTERNOON INTO THIS
EVENING AS CONVECTIVE SHORTWAVE APPROACHES FROM MN AND WARM FRONT IS
DRAPED OVER NRN WI ADN FAR WRN UPR MI. MODIFIED RUC SNDGS FOR 83/57
SHOWS SBCAPE VALUES AROUND 1500 J/KG. HOWEVER...MODEL SNDGS DO SHOW
A CAP ABOVE 800 MB WITH AROUND 100 J/KG CIN TO OVERCOME. GIVEN
APPROACH OF SHORTWAVE FROM MN WOULD EXPECT HEIGHTS TO LOWER AND
CAPPING TO WEAKEN THIS AFTERNOON. THE EXPECTED WEAKENING OF THE CAP
ALONG WITH CONVERGENCE ALONG THE WARM FRONT AND POSSIBLE LAKE BREEZE
BOUNDARIES SHOULD AID IN THUNDERSTORM DEVELOPMENT THIS AFTERNOON.
WILL KEEP LIKELY POPS GOING OVER MUCH OF THE WRN THIRD OF THE FCST
AREA WITH CHC POPS SPREADING CNTRL AND E.

THERE DEFINITELY EXISTS THE POTENTIAL FOR SEVERE STORMS AS WELL...
GIVEN SBCAPES OF AROUND 1500 J/KG...STRONG FAIRLY UNIDIRECTIONAL
DEEP LAYER SHEAR AND THE PRESENCE OF A BROAD 35-45 KT LOW-LEVEL JET
NOSING INTO THE AREA. WET-BULB ZERO HEIGHTS OF BETWEEN 10-11 KFT
WITH THE STRONG SHEAR PRESENT COULD LEAD TO A FEW STORMS PRODUCING
LARGE HAIL AS WELL AS DAMAGING WINDS. ISOLATED TORNADOES NOT OUT OF
THE QUESTION EITHER AS STORMS LIKELY TO BECOME MORE SURFACE BASED BY
LATE AFTERNOON AND STILL HAVE WARM-FRONT BOUNDARY PRESENT. 0-3 KM
STORM-RELATIVE HELICITY VALUES WERE AROUND 250 M2/S2 WITH 0-1 KM
AROUND 125-130 M2/S2 WERE ALSO FAVORABLE FOR TORNADOGENESIS. THUS...
HAVE UPDATED THE HWO TO INCLUDE MENTION OF POSSIBLE ISOLATED
TORNADOES LATE THIS AFTERNOON INTO THIS EVENING.

&&

.DISCUSSION...
CURRENTLY FIRST ROUND OF SHOWERS AND THUNDERSTORMS IMPACTING CENTRAL
UPPER MICHIGAN WITH HEAVY RAIN AND FREQUENT LIGHTNING. MUCAPES OF
500 TO 1000J/KG ROOTED ABOVE H85 RESULTED IN ISOLATED CELLS WITH PEA
TO DIME SIZED HAIL. EDGE OF CAP AT 750MB APPARENT IN REGIONAL RADAR
LOOP WITH CONVECTION ARCING FM NORTHERN MN ACROSS NORTHWEST LK
SUPERIOR AND SE INTO THE ONGOING COMPLEX OVR THE EASTERN HALF OF
UPPER MICHIGAN. A FEW BLIPS SHOWING UP OVR NORTHERN WI...BUT NOTHING
IS BECOMING ORGANIZED OR STRONGER. CONVECTION OVR NORTHERN MN
FEEDING OFF BETTER INSTABILITY TO THE WEST AND ONE CELL PRODUCED SVR
HAIL LAST HOUR. H85 WIND MAX OF 50KT TRANSPORTING MOISTURE INTO
CURRENT THUNDERSTORMS OVR CWA IN PROCESS OF VEERING WSW SO EXPECT
THUNDERSTORMS IN THE EAST THIS MORNING BEFORE FADING AWAY WITH
CAPPING BUILDING OVERHEAD. EXCEPTION WILL BE ALONG EDGE OF CAP WHERE
DISTURBANCES RIDING ALONG US/CANADIAN BORDER WILL KEEP TRIGGERING
CONVECTION THROUGH THE DAY. OTHERWISE...REDUCED POPS TO JUST A
SLIGHT CHANCE TOWARD WI BORDER THROUGH EARLY AFTN AS CAPPING
PREVAILS. AFTER CONVECTION SHIFTS OUT OF AREA...BARRING ANY
WIDESPREAD CLOUD COVER...EXPECT MIXING TO AROUND H85 TO BOOST
TEMPS TO AROUND 80F FOR THE INLAND WEST HALF AS WARM FRONT MOVES TO
NEAR ONT-CMX-MQT-ESC LINE THIS AFTN. MUCH COOLER TEMPS FOR THE EAST
AS SOUTH FLOW ADVECTS MOIST MARINE LAYER OFF LK MICHIGAN. TEMPS NEAR
LK MI WILL PROBABLY STAY IN THE 50S ALL DAY WHILE INLAND PORTIONS OF
EAST WILL STRUGGLE INTO LOWER 60S.

SURFACE BASED CAPE THIS AFTN IN WARM SECTOR INCREASES TO AROUND 1500
J/KG USING A T/TD OF 80/55. ALSO A STRONG CAP STILL PRESENT WITH
VALUES NEAR 100J/KG. SHORTWAVE LEADING TO CONVECTION OVR ND EMERGES
INTO NORTHERN MN BY EARLY AFTN THEN TO WESTERN LK SUPERIOR BY LATE
AFTN. THIS SHORTWAVE WILL HELP LOWER HEIGHTS AND WEAKEN CAPPING SEEN
ON SOUNDINGS...BUT WITH MAIN SFC BOUNDARY JUST ENTERING PICTURE
AROUND 21Z...EXPECT INITIATION TO BE DELAYED UNTIL LATE AFTN. IF
NORTHEAST WINDS ACROSS WESTERN LK SUPERIOR STRENGTHEN THEN THERE MAY
BE A TRIGGER AHEAD OF THE MAIN FRONT AND CONVECTION MAY TRY TO
DEVELOP SLIGHTLY EARLIER OVR NORTHWEST WI INTO FAR WESTERN UPR MI.
LATEST RUC LIKES THIS IDEA...WHEREAS LOCAL WRF-ARW AND NAM/GFS DO
NOT DEVELOP CONVECTION UNTIL LATE IN THE DAY. EVENTUALLY EXPECT THE
0-6KM DEEP LAYER SHEAR OF 40KT WILL TEAM WITH BUILDING INSTABILITY
TO PRODUCE A POTENTIAL OF SEVERE THUNDERSTORMS ACROSS CWA THROUGH
EARLY EVENING. ALL CWA IS INCLUDED IN THE SPC DAY ONE SLIGHT RISK
AREA. LARGE HAIL AND DAMAGING WINDS ARE BOTH POSSIBLE. THUNDERSTORM
THREAT AND POTENTIAL SEVERE STORMS WILL EXIT THE CWA FM W TO E AS
MAIN FRONT SLIDES ACROSS UPR MICHIGAN.

TUE/WED STILL LOOKING COOLER THAN NORMAL WITH SHOWERS AT TIMES.
COOLEST TEMPS TUE IN CYCLONIC N/NE FLOW OVR NORTHWEST AND NORTH
CENTRAL CWA WHILE N WINDS ON WED WILL KEEP EVEN WI BORDER AREAS
COOL. AREAS NEAR LK SUPERIOR WED WILL STRUGGLE TO REACH THE UPR 40S.
FUTURE FORECASTS WILL NEED TO ADDRESS POTENTIAL FOR SNOW TUE NIGHT
INTO WED AS RATHER STRONG SHORTWAVE DIGS INTO THE TROUGH. GFS/NAM
COOLEST WITH THE AIRMASS SHOWING H85 TEMPS DIPPING BLO ZERO. UKMET
AND ECMWF NOT AS COLD. COLDER MODELS WOULD LEAD TO CHANCE OF SNOW TO
MIX WITH RAIN LATE TUE NIGHT OVR HIGHER TERRAIN OF NORTHWEST AND
NORTH CENTRAL. H5 COLD POOL TO -28C LEADS TO DIURNAL SHOWERS ON WED
WHICH WITH THE LOW FREEZING LEVELS AROUND 1KFT MAY CONTAIN SOME SNOW
AS WELL. COOLING IS BRIEF AS WARMER TEMPS ARE EXPECTED BY LATE WEEK
WITH RETURN FLOW DEVELOPING.

COORD WITH APX/GRB.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...NONE.

&&

UPDATE...VOSS
PREV DISCUSSION...JLA

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE MARQUETTE MI
1103 AM EDT MON MAY 14 2007

MIZ001>007-009>014-084-085-151200-
KEWEENAW-ONTONAGON-NORTHERN HOUGHTON-BARAGA-MARQUETTE-ALGER-LUCE-
GOGEBIC-IRON-DICKINSON-MENOMINEE-DELTA-SOUTHERN SCHOOLCRAFT-
SOUTHERN HOUGHTON-NORTHERN SCHOOLCRAFT-
1103 AM EDT (1003 AM CDT) MON MAY 14 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WESTERN UPPER
MICHIGAN AND CENTRAL UPPER MICHIGAN.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON OVER WESTERN
UPPER MICHIGAN ALONG AND NORTH OF A WARM FRONT APPROACHING FROM
NORTHERN WISCONSIN. THE STORMS WILL THEN SPREAD INTO CENTRAL UPPER
MICHIGAN THIS EVENING. SOME OF THE STORMS LATE THIS AFTERNOON AND
THIS EVENING MAY PRODUCE DAMAGING WINDS...HAIL UP TO ONE AND A HALF
INCHES IN DIAMETER AND POSSIBLY EVEN ISOLATED TORNADOES NEAR THE
WARM FRONT.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

A WIDESPREAD FROST IS LIKELY OVER INTERIOR WEST AND CENTRAL UPPER
MICHIGAN LATE WEDNESDAY NIGHT INTO THURSDAY MORNING.

THERE IS A SLIGHT CHANCE OF THUNDERSTORMS SATURDAY NIGHT AND
SUNDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THROUGH THIS EVENING.

LSZ221-241>248-263-264-151200-
KEWEENAW BAY AND HURON BAY FROM LOWER ENTRANCE LIGHT TO PORTAGE
LAKE TO HURON ISLANDS MI-SAXON HARBOR WI TO ONTONAGON MI-
ONTONAGON TO UPPER ENTRANCE OF PORTAGE CANAL MI-
UPPER ENTRANCE OF PORTAGE CANAL TO MANITOU ISLAND MI-
MANITOU ISLAND TO LOWER ENTRANCE OF PORTAGE CANAL MI-
HURON ISLANDS TO MARQUETTE MI-MARQUETTE TO MUNISING MI-
MUNISING TO GRAND MARAIS MI-GRAND MARAIS TO WHITEFISH POINT MI-
LAKE SUPERIOR, EAST OF A LINE FROM SAXON HARBOR WI TO GRAND
PORTAGE, MN, TO A LINE NORTHWARD FROM MANITOU IS. MI, BEYOND 5 NM
AND SOUTH OF THE US/CANADIAN BORDER-
LAKE SUPERIOR, EAST OF A LINE FROM MANITOU IS. MI NORTHWARD
BEYOND 5 NM AND SOUTH OF THE US/CANADIAN BORDER, EXCLUDING
WHITEFISH BAY-
1103 AM EDT (1003 AM CDT) MON MAY 14 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EASTERN LAKE
SUPERIOR...CENTRAL LAKE SUPERIOR AND WESTERN LAKE SUPERIOR.

.DAY ONE...TODAY AND TONIGHT

EXPECT SCATTERED THUNDERSTORMS THIS AFTERNOON THROUGH THIS EVENING
OVER ALL OF LAKE SUPERIOR. THE THREAT OF THUNDERSTORMS WILL LINGER
THROUGH MUCH OF TONIGHT OVER FAR SOUTHEAST LAKE SUPERIOR BEFORE
ENDING LATE. A FEW OF THE STRONGER THUNDERSTORMS THIS AFTERNOON AND
EVENING COULD PRODUCE LARGE HAIL...STRONG WINDS AND POSSIBLY EVEN A
FEW WATERSPOUTS...ESPECIALLY OVER SOUTHERN PORTIONS OF THE LAKE.

EXPECT AREAS OF FOG TODAY AND TONIGHT. THE FOG COULD BE DENSE...
REDUCING VISIBILITY TO ONE-QUARTER MILE OR LESS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

AREAS OF FOG WILL LINGER OVER CENTRAL AND EASTERN LAKE SUPERIOR
UNTIL EARLY TUESDAY AFTERNOON.

THERE IS A SLIGHT CHANCE OF THUNDERSTORMS SATURDAY NIGHT AND
SUNDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED.

LMZ221-248-262-151200-
BAY OF GREEN BAY NORTH OF LINE FROM CEDAR RIVER MI TO ROCK ISLAND
PASSAGE-SEUL CHOIX POINT TO POINT DETOUR MI-
LAKE MICHIGAN...FROM SEUL CHOIX POINT TO ROCK ISLAND
PASSAGE...SOUTHEASTWARD BEYOND 5 NM OFF SHORE TO THE MID-
LINE OF THE LAKE-
1103 AM EDT MON MAY 14 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHERN LAKE
MICHIGAN.

.DAY ONE...TODAY AND TONIGHT

EXPECT SCATTERED THUNDERSTORMS THIS AFTERNOON AND TONIGHT. THE
THUNDERSTORMS WILL BE MOST NUMEROUS DURING THE EVENING. A FEW OF THE
STRONGER THUNDERSTORMS THIS EVENING COULD PRODUCE LARGE HAIL AND
STRONG WINDS.

EXPECT AREAS OF FOG TODAY AND TONIGHT. THE FOG COULD BE DENSE...
REDUCING VISIBILITY TO ONE-QUARTER MILE OR LESS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THERE IS A SLIGHT CHANCE OF THUNDERSTORMS SATURDAY NIGHT AND
SUNDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED.

VOSS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MARQUETTE MI
124 PM EDT MON MAY 14 2007

MIZ005-141815-
MARQUETTE-
124 PM EDT MON MAY 14 2007

...STRONG THUNDERSTORM MOVING ACROSS MARQUETTE COUNTY...

AT 122 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 5 MILES SOUTHWEST OF CHAMPION...OR 17 MILES WEST
OF ISHPEMING...MOVING EAST AT 30 MPH.

ONE HALF INCH DIAMETER HAIL...WINDS UP TO 40 MPH...AND HEAVY
DOWNPOURS ARE EXPECTED WITH THIS STORM.

* LOCATIONS IN OR NEAR THE PATH INCLUDE...
  REPUBLIC.
  NATIONAL MINE.
  NEGAUNEE.
  SANDS.

STAY TUNED TO NOAA WEATHER RADIO...COMMERCIAL RADIO...OR YOUR LOCAL
TELEVISION STATIONS FOR LATER STATEMENTS AND POSSIBLE WARNINGS
CONCERNING THIS WEATHER SITUATION.