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000
FXUS63 KAPX 212307 AAA
AFDAPX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GAYLORD MI
707 PM EDT TUE MAY 21 2013

.SYNOPSIS...
ISSUED AT 427 PM EDT TUE MAY 21 2013

THE STORM SYSTEM WHICH SETTLED INTO THE PLAINS EARLIER THIS WEEK...
WILL SLOWLY MOVE OVER THE GREAT LAKES WEDNESDAY...BEFORE FINALLY
EXITING EAST ON THURSDAY. THIS PATTERN WILL CONTINUE TO GENERATE
MILD TEMPERATURES THIS WEEK...ALONG WITH SEVERAL CHANCES FOR SHOWERS AND
THUNDERSTORMS.

HIGH PRESSURE WILL BUILD INTO THE GREAT LAKES FRIDAY AND SATURDAY.
THIS PATTERN WILL GENERATE PLENTY OF SUN AND SEASONAL TEMPERATURES...
OVER NORTHERN MICHIGAN THROUGH THE UPCOMING HOLIDAY WEEKEND.

&&

.UPDATE...
ISSUED AT 701 PM EDT TUE MAY 21 2013

CHANGES THIS HOUR: ADJUSTMENTS TO POPS/WEATHER BASED ON CONVECTIVE
DEVELOPMENT ALONG/JUST NORTH OF LAKE BREEZE/WARM FRONTAL BOUNDARY
WHICH HAS RESULTED IN SOME MODEST STORMS LIKELY PRODUCING SOME
SMALL HAIL ATTM BASED ON RADAR SIGNATURES. OTHERWISE...ANEMIC
SHRA ACTIVITY IS BEGINNING TO ARRIVE OVER THE COAST OF NW LOWER
AHEAD OF SURFACE COLD FRONT. A DOWNWARD TREND IN PRECIP CHANCES
STILL LOOKS GOOD AS WE LOSE DAYTIME HEATING...WITH FOG THAT IS NOW
FROM THE STRAITS NORTH LIKELY EXPANDING SOUTHWARD HEADING INTO THE
EVENING.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 427 PM EDT TUE MAY 21 2013

OVERVIEW: BROAD...CLOSED LOW LINGERS OVER THE NRN PLAINS. ASSOCIATED
SFC LOW OVER WESTERN WISCONSIN WITH A STALLED FRONT STRETCHING
EASTWARD THROUGH NRN LOWER MICHIGAN...ROUGHLY THROUGH THE M-32
CORRIDOR. LOW CLOUDS HAVE ERODED OVER MOST OF NRN LOWER MICHIGAN
ALLOWING MOST LOCATIONS SOUTH OF THE FRONT TO WARM INTO THE MID TO
UPPER 70S. NORTH OF THE FRONT...EASTERLY FLOW OFF LAKE HURON HAS KEPT
TEMPS IN THE 50S AND 60S ACROSS THE TIP OF THE MITT...SORRY. STILL
CLOUDY AND COOL IN THE EASTERN U.P.

ALSO SOUTH OF THE FRONT...HEATING HAS PUSHED 100 MB MIXED LAYER CAPE
VALUES UP OVER 500 J/KG AND WE DO HAVE A SMALL CLUSTER OF THUNDERSTORMS
THAT INITIALLY DEVELOPED OVER SW LOWER MICHIGAN ALONG THE MARINE
BOUNDARY...WORKING NORTHEASTWARD THROUGH THE ALMA AND MOUNT
PLEASANT AREA. THOSE STORMS WILL JUST MISS THE FAR SE COUNTIES.

TONIGHT...RUNNING OUT OF TIME FOR CONVECTION. VISIBLE SATELLITE
IMAGERY REVEALING AGITATED CU ACROSS INLAND NRN LOWER MICHIGAN.
STILL CANNOT RULE OUT SOMETHING POPPING OVER THE NEXT COUPLE OF
HOURS. BUT IN THE ABSENCE OF ANY BROADER SCALE UPWARD FORCING...THERE
MAY JUST NOT BE ENOUGH LOW LEVEL CONVERGENCE TO FORCE MOIST CONVECTION
TODAY. THERE IS CONVECTION OCCURRING IN EASTERN WISCONSIN SOME OF
WHICH IS STARTING TO SWING NORTHEASTWARD OUT INTO LAKE MICHIGAN.
BUT BEING SFC BASED I DOUBT IT WILL SURVIVE THE TRIP ACROSS THE
LAKE INTO NRN LOWER MICHIGAN. HAVE LOWERED POPS TO JUST CHANCE
ACROSS INLAND NRN LOWER MICHIGAN FOR THE LATE AFTERNOON/EARLY
EVENING TIMEFRAME. ALSO HAVE A SMALL AREA OF CHANCY POPS IN
WESTERN CHIP/MACK COUNTIES IN CASE SOMETHING SWINGS UP THROUGH
THERE OUT OF WISCONSIN. BUT I THINK THATS ABOUT IT FOR PRECIP
TONIGHT DESPITE THE RATHER WET LOOK TO THE MODELS.

OTHERWISE...QUIET CONDITIONS WITH MORE FOG DEVELOPMENT AGAIN
TONIGHT...ESPECIALLY NORTH OF THE FRONT INTO EASTERN UPPER WHERE
THEY ALREADY HAVE FOG (SORRY).

WEDNESDAY...CLOSED SYSTEM FINALLY BEGINS TO WORK ITS WAY THROUGH
THE GREAT LAKES REGION. EXPECT ONE MORE WAVE AND ASSOCIATED SFC
LOW/MOISTURE SURGE TO SWING UP INTO THE GREAT LAKES THROUGH THE
DAY BRINGING ANOTHER ROUND OF FAIRLY WIDESPREAD RAINFALL TO THE
CWA. A COOLER/WET DAY OVERALL WITH THUNDER POTENTIAL LARGELY
FURTHER SOUTH WHERE BETTER INSTABILITY WILL RESIDE.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY) ISSUED AT 427 PM
EDT TUE MAY 21 2013

THE SLOW MOVING AMPLIFIED TROUGH THAT HAS GENERATED THE RAIN AND
THUNDERSTORMS THE PAST FEW DAYS FINALLY BEGINS TO MOVE THROUGH THE
GREAT LAKES REGION WEDNESDAY NIGHT...ENDING RAIN CHANCES THROUGHOUT
THE DAY THURSDAY FROM NORTHWEST TO SOUTHEAST. THERE WILL BE A COOL
DOWN ONCE THIS TROUGH MOVES THROUGH THE GREAT LAKES REGION WITH
CHILLY FRIDAY AND SATURDAY MORNINGS AND MAX TEMPERATURES ONLY
REACHING INTO THE MID 50S TO MID 60S THURSDAY AND RIGHT ON THROUGH
THE MEMORIAL DAY WEEKEND.

WEDNESDAY NIGHT THROUGH FRIDAY MORNING...THUNDERSTORM CHANCES
DIMINISH WEDNESDAY NIGHT AS THE LOW PRESSURE SYSTEM CENTERS ITSELF
OVER MICHIGAN...ALTHOUGH CONTINUING TO PRODUCE RAIN THROUGHOUT THE
NIGHT. NORTHERLY WINDS BEHIND THIS SYSTEM POSSIBLY RAMP UP TO GALE
FORCE  OVER THE LAKE MICHIGAN SHORELINE...WAITING FOR MORE
CONFIDENCE AND LEAVING IT UP TO THE MIDNIGHT SHIFT TO POSSIBLY HOIST
A GALE WATCH THROUGH THURSDAY AFTERNOON. AGEOSTROPHIC WINDS OF LESS
THAN 10KTS...INDICATE DECOUPLING TAKING PLACE THURSDAY NIGHT. ALONG
WITH THE LIGHT WINDS AND CLEAR SKIES COMES...WHAT APPEARS TO BE A
VERY GOOD CHANCE OF FROST THURSDAY NIGHT INTO EARLY FRIDAY
MORNING...WITH TEMPERATURES DOWN TO THE LOW 30S AND POSSIBLY EVEN
THE UPPER 20S IN INTERIOR PORTIONS OF NORTHERN LOWER MICHIGAN
FROST/FREEZE HEADLINES MAY HAVE TO BE PUT OUT. AM GOING TO WIDEN
THE MENTION OF FROST IN THE GRIDS TO MOST OF NORTHERN LOWER MICHIGAN.

MEMORIAL DAY WEEKEND (FRIDAY THROUGH MONDAY)...MODELS ARE STILL IN
AGREEMENT WITH A LARGE HIGH PRESSURE CENTER BUILDING OVER NORTHERN
MICHIGAN KEEPING THE CURRENT FORECAST ON TRACK FOR A DRY HOLIDAY
WEEKEND. IT WILL BE CHILLIER THAN WHAT WE HAVE SEEN THE PAST SEVERAL
DAYS WITH 850MB TEMPERATURES ONLY AROUND 0C...BUT LUCKILY THE SUNNY
SKIES AND LIGHT WINDS SHOULD MAKE UP FOR IT. ALTHOUGH IT WILL MOST
LIKELY BE CHILLY IF YOUR PLAYING IN OR NEAR ANY BODY OF WATER...AS
LAKE TEMPERATURES ARE STILL PRETTY COLD. FRIDAY NIGHT INTO EARLY
SATURDAY MORNING MAY SEE FROST ONCE AGAIN...WITH VERY LIGHT WINDS
AND CLEAR SKIES ALLOWING RADIATIONAL COOLING TO DROP TEMPERATURES
SLIGHTLY WARMER THAN FRIDAY MORNING...INTO THE LOW 30S...OVER
INTERIOR PORTIONS OF NORTHERN LOWER MICHIGAN...HENCE ANOTHER
POSSIBLE FROST HEADLINE.

TUESDAY...MODELS ARE IN AGREEMENT OF THE NEXT SYSTEM DEVELOPING OVER
THE CENTRAL PLAINS AND MOVING INTO THE GREAT LAKES REGION...BUT THE
TIMING IS VERY UNCERTAIN STILL...WITH ANYWHERE FROM LATE TUESDAY
NIGHT TO WEDNESDAY NIGHT BEING POSSIBILITIES. WITH THE LARGE AREA
OF HIGH PRESSURE DOMINATING THE EASTERN US AND THE ECMWF GOING FOR A
MORE WEDNESDAY TIMEFRAME...I AM KEEPING TUESDAY DRY FOR NOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 215 PM EDT TUE MAY 21 2013

VFR CONDITIONS DEVELOPING AT THE TAF SITES FOR THE AFTERNOON
HOURS. MAY SEE SOME POP-UP SHOWERS/THUNDERSTORMS AFTER 20Z...THAT
WOULD IMPACT MAINLY APN. OTHERWISE...LIGHT WINDS/MOIST LOW LEVELS
MAY LEAD TO MORE FOG DEVELOPMENT THIS EVENING/OVERNIGHT...ESPECIALLY
AT PLN AND APN.

WEDNESDAY...WAVE OF LOW PRESSURE WILL ADVANCE THROUGH THE REGION
BRINGING ANOTHER BATCH OF SHOWERS AND THUNDERSTORMS TO THE REGION.


&&

.MARINE...
ISSUED AT 427 PM EDT TUE MAY 21 2013

MAINLY LIGHT WINDS WILL BE FELT ON THE GREAT LAKES TONIGHT THROUGH
WEDNESDAY...WITH NO HEADLINES ANTICIPATED. LOW PRESSURE SYSTEM
WORKS THROUGH THE WESTERN GREAT LAKES BY WEDNESDAY NIGHT WITH
GUSTY NORTH-NORTHEAST WINDS DEVELOPING WEDNESDAY NIGHT THROUGH
THURSDAY WITH GALE FORCE GUSTS POSSIBLE FOR SOME NEARSHORE AREAS.


&&

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

&&

$$

UPDATE...ARNOTT
SYNOPSIS...SR
SHORT TERM...BA
LONG TERM...TL
AVIATION...BA
MARINE...BA