Severe Thunderstorm Warning 123, NWS Gaylord, MI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
729 PM EDT THU JUL 17 2008

.AVIATION...VERY IFFY TAF FCST THE NEXT 6 HOURS OWING TO INCOMING
MCS AND REMNANT INSTABILITY IN PLACE ACRS THE REGION. AT THIS
POINT...APPEARS KPLN/KAPN ARE IN FOR A ROUND OF QUITE HEAVY RAIN
AT TIMES THRU THE LATE EVENING...WITH PERIODIC IFR OR LOWER
VISBYS. KTVC MUCH MORE TRICKY WITH BEST FORCING VIA LOW LEVEL JET
FOCUSED TO THE NORTH...AND WILL ATTEMPT TO KEEP THINGS DRY FOR THE
MOST PART. OTHERWISE...COULD SEE A RENEWED LINE OF SHRA/TSRA LATER
TONIGHT AS SFC FRONT DROPS BACK SOUTH...BUT CONFIDENCE ON THIS
SCENARIO RATHER LOW GIVEN ONGOING CONVECTION/LIKELY SUBSIDENCE IN
ITS WAKE. FRONT MAY THEN BECOME ACTIVE ONCE AGAIN TOMROROW...WITH
BEST CHANCES FROM KAPN TO KTVC ON SOUTH.

LAWRENCE

&&

.PREV DISCUSSION... /ISSUED 349 PM EDT THU JUL 17 2008/

DISCUSSION...QUITE LIKELY AN ACTIVE NIGHT ACROSS NRN MICHIGAN...
WITH BOTH SEVERE WEATHER AND HEAVY RAINFALL POSSIBLE. MLCAPES OF
1000-2000 J/KG LATE THIS AFTERNOON...TOGETHER WITH LAKE HURON LAKE
BREEZE CONVERGENCE...HAS FUELED SCATTERED STRONG TO SEVERE STORMS
OVER MAINLY NE LOWER. ACTIVITY WILL CONTINUE INTO THE EVENING...WITH
NEW STORMS LIKELY POPPING UP. THE REAL ACTION...HOWEVER...WILL BE
LATER THIS EVENING AS IMPRESSIVE COMPLEX OF STORMS CURRENTLY OVER WI
ROLLS INTO REGION.

STORMS WILL PUSH INTO A LARGELY UNTAPPED AIR MASS OVER ERN WI AND
WRN LOWER MI...WHERE MLCAPES EXCEED 1000 J/KG. 0-6 KM BULK SHEAR
AROUND 30 KT...0-3 KM BULK SHEAR AROUND 30 KT...AND UNIDIRECTIONAL
850-500 MB FLOW SUGGEST QUASI-LINEAR MCS WILL PUSH ACROSS LAKE
MICHIGAN INTO NW LOWER AND ERN UPPER MICHIGAN THIS EVENING.
MARGINALLY SEVERE HAIL AND DAMAGING WINDS WILL BE POSSIBLE. EXPECT
COMPLEX TO REACH NW LOWER COAST AROUND 00Z...PUSHING ENE ACROSS TIP
OF THE MITT AND ERN UPPER.

HEAVY RAIN POTENTIAL ALSO APPEARS VERY GOOD...WITH PWATS OVER 1.75
INCH...H8 DEW POINTS NEAR +13C...FREEZING LEVELS ABOVE 13 KFT...
20-30KT H8 LLJ...AND 850-300 MB WIND PROFILES LIKELY SUPPORTING
TRAINING CELLS. LOCALIZED RAINFALL AMOUNTS OF 1-3 INCHES LIKELY.
AREAS ALONG/NORTH OF A LINE FROM TVC-GRAYLING-APN WILL MOST LIKELY
BE IMPACTED.

SMITH

LONG TERM (FRIDAY THROUGH THURSDAY)...AN EXTENDED FORECAST BESET
WITH UNCERTAINTIES (ESPECIALLY THROUGH EARLY NEXT WEEK) CONTINUES AS
HARD-TO-TIME WAVES TRAVERSING RELATIVELY ZONAL NORTHERN
CONUS/SOUTHERN CANADA MID AND UPPER LEVEL FLOW INTERACT WITH A WAVY
GREAT LAKES FRONTAL SYSTEM. FURTHER EXACERBATING THE FORECAST DELIMA
IS IMPOSSIBLE TO DETERMINE AFFECTS OF ANTICIPATED DAILY CONVECTION
ALONG AFOREMENTIONED FRONTAL SYSTEM...WITH THE EXPECTATION THAT ANY
CONVECTIVELY DRIVEN CONGEALED COLD POOL/DIFFERENTIAL HEATING
BOUNDARIES WILL SERVE AS FURTHER SOURCES OF CONVECTIVE DEVELOPMENT.
FORECAST CHALLENGES CENTER ON SHOWER AND THUNDERSTORM POTENTIAL
THROUGH MONDAY.

AS ALREADY MENTIONED...QUESTIONS ABOUND TO START THE LONG TERM
FORECAST...SPECIFICALLY WITH HOW FAR SOUTH NORTHERN MICHIGAN COLD
FRONT SAGS ON FRIDAY. THAT BEING SAID...IN ALL REALITY...ACTUAL FRONTAL
PLACEMENT MIGHT HAVE LITTLE TO SAY WITH REGARDS TO RENEWED
CONVECTIVE DEVELOPMENT. PRIMARY IMPETUS FOR FRIDAY SHOWER AND
THUNDERSTORMS MORE LIKELY TIED TO SOUTHWARD DIVING CONGEALED COLD
POOL AND DIFFERENTIAL HEATING LINE FROM TONIGHTS ANTICIPATED
NORTHERN MICHIGAN/EASTERN UPPER MCS. IN ALL HONESTY...STILL WAY TO
EARLY TO FIGURE WHERE THIS WILL SET UP...SO HAVE DONE LITTLE TO
INHERITED POP AND WEATHER GRIDS...FEATURING HIGH CHANCE POPS ALONG
AND SOUTH OF M-32. WHILE SEVERE THREAT APPEARS MINIMAL WITH FREEZING
LEVELS PUSHING 14.5KFT AND BETTER MID LEVEL WIND FIELD TO OUR
NORTH...HEAVY RAIN THREAT REMAINS GIVEN SKINNY CAPE PROFILE...DECENT
WARM CLOUD DEPTH RAIN PROCESSES...AND PWATS > 1.5 INCHES. FRONT
SHOULD SAG SOUTH OF THE AREA FRIDAY NIGHT...REMAINING THERE THROUGH
SATURDAY...AS SEASONABLY STRONG HUDSON BAY HIGH PRESSURE FLEXES IT
MUSCLE. WITH QUESTIONS REMAINING JUST HOW FAR SOUTH FRONT
PROGRESSES...HAVE MAINTAINED LOW POP MENTION FOR SOUTHERN ZONES (DID
MANAGE TO TRIM THE NORTHERN EXTENT SOME). MORE POTENT SHORTWAVE
DIVING ACROSS THE NORTHERN CONUS REINVIGORATES SOUTHWEST RETURN FLOW
LATE SATURDAY AFTERNOON THROUGH SUNDAY...GIVING A NORTHWARD SHOVE TO
SOUTHERN MICHIGAN FRONTAL SYSTEM. THIS...COUPLED WITH REMAINING
MOISTURE RICH ATMOSPHERE SHOULD BRING ANOTHER THREAT OF SHOWERS AND
STORMS. WHILE MUCH TOO EARLY TO ASCERTAIN SEVERE THREAT...DECENT
DYNAMICS AND DEEP MOISTURE COULD MAKE THINGS
INTERESTING...ESPECIALLY SATURDAY NIGHT AND SUNDAY.

SERIES OF MID LEVEL WAVES EXPECTED TO CONGEAL INTO A CLOSED SOUTHERN
CANADA LOW EARLY NEXT WEEK AND PIVOT OFF TO THE NORTHEAST. LATEST
GFS TRENDS SUPPORT OVERNIGHT ECMWF...SHOWING A FARTHER NORTH AND
MORE PROGRESSIVE SOLUTION (CLIMATOLOGICALLY MORE FAVORED). CURRENT
THINKING REMAINS VIRTUALLY UNCHANGED FROM YESTERDAY...WITH LINGERING
LIGHT SHOWERS MONDAY GIVING WAY TO A POSSIBLE EXTENDED DRY PERIOD
MONDAY NIGHT THROUGH THURSDAY AS SYSTEM PULLS TO THE NORTHEAST...
ALLOWING MID LEVEL RIDGE AXIS TO CREST THE REGION.

MSB

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
LH...NONE.
LS...NONE.
&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GAYLORD MI
405 PM EDT THU JUL 17 2008

LHZ345>349-LMZ323-341-342-344>346-LSZ321-322-MIZ008-015>036-041-042-
181000-
STRAITS OF MACKINAC-ST IGNACE TO FALSE DETOUR CHANNEL-
MACKINAC BRDG TO PRESQUE ISLE LT-PRESQUE ISLE LT TO STURGEON PT-
STURGEON PT TO ALABASTER-GRAND TRAVERSE BAY-
SEUL CHOIX PT TO MACKINAC BRDG-NORWOOD TO MACKINAC BRDG-
SLEEPING BEAR PT TO GRAND TRAVERSE LT-PT BETSIE TO SLEEPING BEAR PT-
MANISTEE TO PT BETSIE-WHITEFISH BAY-ST. MARYS RIVER-CHIPPEWA-
MACKINAC-EMMET-CHEBOYGAN-PRESQUE ISLE-CHARLEVOIX-LEELANAU-ANTRIM-
OTSEGO-MONTMORENCY-ALPENA-BENZIE-GRAND TRAVERSE-KALKASKA-CRAWFORD-
OSCODA-ALCONA-MANISTEE-WEXFORD-MISSAUKEE-ROSCOMMON-OGEMAW-IOSCO-
GLADWIN-ARENAC-
405 PM EDT THU JUL 17 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF LAKE HURON...LAKE
MICHIGAN...LAKE SUPERIOR...EASTERN UPPER MICHIGAN AND NORTHERN LOWER
MICHIGAN.

.DAY ONE...TONIGHT

THUNDERSTORMS CAN BE EXPECTED ACROSS MUCH OF NORTHERN LOWER AND
EASTERN UPPER MICHIGAN TONIGHT. SOME OF THESE STORMS MAY BE SEVERE.

THE GREATEST THREAT FOR SEVERE WEATHER THROUGH EARLY THIS
EVENING WILL BE EAST OF THE I-75 CORRIDOR. THE THREAT WILL THEN
SHIFT TO AREAS ALONG AND NORTH OF A LINE FROM MANISTEE TO
HARRISVILLE. PENNY SIZED HAIL AND WIND GUSTS TO 60 MPH WILL BE THE
MAIN THREATS.

IN ADDITION...HEAVY RAINFALL IS POSSIBLE TONIGHT...WITH 1 TO 2
INCHES OF RAINFALL LIKELY IN SOME LOCALES. THE TORRENTIAL RAIN WILL
PRODUCE LIMITED VISIBILITIES...PONDING OF WATER ON ROADWAYS...AND
POSSIBLY LOCALIZED FLOODING. THE HEAVY RAIN IS EXPECTED NORTH OF A
LINE FROM MANISTEE TO ALPENA...INCLUDING TRAVERSE CITY...GAYLORD...
CHEBOYGAN...AND SAULT STE. MARIE.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORMS REMAIN POSSIBLE ACROSS NORTHERN MICHIGAN FRIDAY...AND
ACROSS PORTIONS OF NORTHERN LOWER MICHIGAN FRIDAY NIGHT AND
SATURDAY. A FEW SEVERE STORMS ARE POSSIBLE FRIDAY AFTERNOON INTO THE
EVENING...WITH DAMAGING WIND GUSTS AND HEAVY RAIN THE MAIN THREAT.

THUNDERSTORMS ARE POSSIBLE AGAIN SATURDAY NIGHT THROUGH SUNDAY NIGHT
ACROSS ALL OF NORTHERN MICHIGAN.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TONIGHT.

BBS/MSB

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GAYLORD MI
505 PM EDT THU JUL 17 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0345 PM     HAIL             10 E HILLMAN            45.07N 83.70W
07/17/2008  M0.88 INCH       ALPENA             MI   TRAINED SPOTTER

            WINDS ESTIMATED TO 60 MPH AS WELL.

&&

LAWRENCE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GAYLORD MI
648 PM EDT THU JUL 17 2008

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0640 PM     FLASH FLOOD      7 S HUBBARD LAKE        44.70N 83.59W
07/17/2008                   ALCONA             MI   LAW ENFORCEMENT

            MOUNT MARIA ROAD FLOODED NEAR SOUTH END OF HUBBARD LAKE.

&&

JPB