Marine Hail in Lake Huron, July 19, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
405 PM EDT THU JUL 19 2007

.DISCUSSION...THE MAIN 500 MB SHORTWAVE/COLD CORE IS OVER THE
STRAITS AND HAS BEEN TOUCHING OFF MORE THUNDERSTORMS OVER NORTHERN
LAKES MICHIGAN AND HURON. NORTH OF THIS, THE HEIGHTS BEGIN TO BUILD
AND THE RAIN SHOWERS THAT WERE ASSOCIATED WITH THE WAVE HAVE BEEN
DIMINISHING ON THE MONTREAL RIVER RADAR. A SFC HIGH IS OVER THE
NORTHERN PLAINS. THE MAIN CONCERN WITH THE PACKAGE IS THE CESSATION
OF THE RAIN TONIGHT AND THE WARM UP LATER IN THE WEEK.

TONIGHT...WILL HAVE SCT-NMRS POPS THROUGH 00Z WITH THE STORMS AND
SHOWERS, AND THEN LEFT IN THE POPS TO NE LOWER AFTER 00Z WITH THE
SHOWERS IN CANADA THAT LOOK LIKE THEY WILL CONTINUE ON THEIR WAY
INTO NE LOWER. OTHERWISE, THE CLOUDS WILL BEGIN TO CLEAR OVERNIGHT
AS THE HIGH MOVES IN AND THE MOISTURE DIMINISHES.

LUTZ

FRIDAY AND FRIDAY NIGHT...LARGE AREA OF HIGH PRESSURE EXPECTED TO
BUILD INTO THE WESTERN GREAT LAKES WITH DRY AND NOTICEABLY COOLER
CONDITIONS ANTICIPATED (UPPER 60S TO LOWER 70S). NAM/GFS MODEL
SOUNDINGS AS WELL AS RH PLAN VIEW FORECASTS DRAG SOME LOWER LEVEL
MOISTURE OUT OF ONTARIO (SEEN ON SATELLITE IMAGERY NORTH OF SUPERIOR
THIS AFTERNOON) DOWN THROUGH NRN MICHIGAN LATE OVERNIGHT THROUGH
FRIDAY MORNING. IN ADDITION...MAY ALSO BE A FEW LAKE CLOUDS DRIFTING
OFF LAKES MICHIGAN AND HURON FRIDAY MORNING ON THE NORTHERLY
FLOW...WITH SOME SHALLOW LOW LEVEL CONDITIONAL INSTABILITY NOTED ON
MODEL SOUNDINGS OVER THE LAKES (ALTHOUGH THE MIXED LAYER PROBABLY
TOO SHALLOW AND INVERSION ABOVE TOO STRONG TO SUPPORT THIS NOTION).
IN ANY EVENT...PLAN TO START THE DAY WITH PARTLY CLOUDY SKIES FOR
MOST AREAS PARTICULARLY NEAR LAKES MICHIGAN AND HURON. BY
AFTERNOON...MODEL SOUNDINGS TODAY DEPICT A MUCH DEEPER MIXED LAYER
THAN PREVIOUS FORECASTS AND SUGGEST SCT AFTERNOON CU DEVELOPMENT
PARTICULARLY ACROSS THE HIGHER TERRAIN OF NRN LOWER MICHIGAN.
FOR FRIDAY NIGHT...AFTERNOON CU SHOULD FADE IN THE EARLY EVENING
WITH LOSS OF HEATING LEAVING MAINLY CLEAR SKIES AND DIMINISHING
WINDS. THIS WILL SET THE STAGE FOR TEMPS DROPPING INTO THE 40S
DURING THE NIGHT WITH THE LOWEST READINGS AT THE USUAL COLD SPOTS
(PLN/GOV/MIO...ETC).

SATURDAY AND SUNDAY...SHARP UPPER RIDGE FORECAST TO SLOWLY NUDGE
INTO THE REGION WHILE LARGE EXPANSE OF SFC HIGH PRESSURE REMAINS
ACROSS THE GREAT LAKES AND EAST COAST. WITH THE MID LEVEL
TROUGH/COOLER AIR RETREATING TO THE EAST EXPECT TEMPERATURES TO
REBOUND INTO THE 70S FOR SATURDAY AND BACK TO NEAR 80 BY SUNDAY. SO
A VERY NICE WEEKEND IN STORE FOR NRN MICHIGAN. ONLY CAVEAT...MODEL
RH FORECASTS HINT AT SOME MID AND HIGH LEVEL WARM ADVECTION CLOUD
COVER DEVELOPING ALONG THE EASTERN PERIPHERY OF THE ADVANCING RIDGE
POTENTIALLY BRINGING SOME CLOUD COVER THROUGH THE STATE DURING THE
COURSE OF THE WEEKEND. BUT PROBABLY NO WORSE THAN PARTLY CLOUDY
CONDITIONS AT TIMES.

LATER PERIODS (MONDAY THROUGH THURSDAY)...MEDIUM RANGE GUIDANCE
CONTINUES TO ADVERTISE HIGH AMPLITUDE TROUGH/RIDGE/TROUGH PATTERN
FLATTENING INTO A BROAD MID LEVEL RIDGE PATTERN DURING THE COURSE OF
THE WEEK (IN EXCESS OF 588 DM)...AND ENCOMPASSING MUCH OF THE U.S.
THUS...THE ADVERTISED WARMING TREND STILL LOOKING GOOD WITH TEMPS
REBOUNDING WELL INTO THE 80S AND PERHAPS TOUCHING 90 BY MIDWEEK.
HOWEVER...STILL SOME MODEL DIFFERENCES AMONG THE ECMWF/GFS TO WORK
OUT...SPECIFICALLY WITH THE HANDLING OF THE TROUGH IN THE NORTHEAST
WHICH THE ECMWF CONTINUES TO PINCH OFF...WEAKEN AND SLOWLY
RETROGRADE BACK THROUGH THE REGION. NOT A LOT GOING FOR THIS FEATURE
IN TERMS OF PRECIP CHANCES EVEN IF THIS COMES TO PASS OTHER THAN TO
POSSIBLY TEMPER THE WARMING TREND. AT THE OTHER END OF THE
SPECTRUM...LAST COUPLE GFS RUNS AS WELL AS NCEP MANUAL GUIDANCE
DEPICTING PSEUDO-BACKDOOR COLD FRONT SWINGING DOWN THROUGH NRN
MICHIGAN DURING THE LATE MONDAY/MONDAY NIGHT TIMEFRAME...POTENTIALLY
BRINGING A CHANCE FOR RAINFALL IF THIS COMES TO PASS. BUT GIVEN THE
UNCERTAINTIES OVER HOW THINGS WILL PLAY OUT WILL NOT BITE ON THIS
IDEA EITHER. FOR NOW PLAN IS TO KEEP A DRY FORECAST GOING THROUGH
THE PERIOD AND DEFER ADDING ANY POPS TO LATER FORECAST ISSUANCES.

ADAM

&&

.AVIATION...ISSUED AT 201 PM.

A COLD FRONT WILL CONTINUE TO PUSH THROUGH THE REMAINDER OF NORTHERN
MICHIGAN THIS AFTERNOON...PRODUCING SCATTERED SHOWERS AND
THUNDERSTORMS. COOLER AND DRIER AIR WILL OVERSPREAD THE AREA
TONIGHT. HOWEVER...BEFORE THE DRIER AIR INVADES...A PERIOD OF MVFR
CEILINGS ARE POSSIBLE AROUND KPLN AND KTVC. OUTSIDE OF A FEW 2-3KFT
CEILINGS THIS EVENING...VFR WILL BE DOMINANT LATE TONIGHT...INTO
FRIDAY.

KAS

&&

.APX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GAYLORD MI
434 PM EDT THU JUL 19 2007

LHZ345>349-361-362-LMZ323-341-342-344-345-363-LSZ321-322-MIZ008-
015>036-041-042-201000-
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-MICHIGAN WATERS OF NORTHERN LAKE HURON-
MICHIGAN WATERS OF CENTRAL LAKE HURON-GRAND TRAVERSE BAY-
SEUL CHOIX PT TO MACKINAC BRDG-NORWOOD TO MACKINAC BRDG-
SLEEPING BEAR PT TO GRAND TRAVERSE LT-MANISTEE TO SLEEPING BEAR PT-
MICHIGAN WATERS OF NORTHERN LAKE MICHIGAN-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-
434 PM EDT THU JUL 19 2007

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

.DAY ONE...LATE THIS AFTERNOON AND TONIGHT

THUNDERSTORMS WILL OCCUR ACROSS PORTIONS OF EASTERN UPPER AND
NORTHERN LOWER MICHIGAN THROUGH 8 PM THIS EVENING. BEST CHANCE FOR
STORMS WILL BE FOUND EAST OF U.S. 131 AND NORTH OF M-72 IN LOWER
MICHIGAN INCLUDING LOCATIONS AROUND CHEBOYGAN...ROGERS CITY...
GAYLORD AND ALPENA. A FEW STORMS MAY PRODUCE HAIL UP TO ONE INCH IN
DIAMETER AS WELL AS WIND GUSTS IN EXCESS OF 50 MPH.

THERE IS AN INCREASED RISK FOR RIP CURRENTS TONIGHT ON LAKE MICHIGAN
AND LAKE HURON BEACHES OF NORTHERN LOWER MICHIGAN.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED LATE THIS AFTERNOON AND EARLY
EVENING...HOWEVER SPOTTERS ARE ALWAYS ENCOURAGED TO REPORT ANY WEATHER
DEEMED SIGNIFICANT.

ADAM

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GAYLORD MI
413 PM EDT THU JUL 19 2007

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

0405 PM     WATERSPOUT       10 E OSSINEKE           44.91N 83.23W
07/19/2007                   LHZ348             MI   LAW ENFORCEMENT

&&

KAS