Area Forecast Discussion
Issued by NWS Gaylord, MI

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049
FXUS63 KAPX 051056
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
656 AM EDT THU MAY 5 2016

.UPDATE...
ISSUED AT 640 AM EDT THU MAY 5 2016

A LOW STRATUS DECK HAS FORMED FROM YESTERDAY`S MOISTURE TRAPPED
UNDER THE INVERSION. THIS WILL ERODE AS THE SUN GETS HIGHER AND
MIXING BEGINS TO TAKE PLACE. THOSE AREAS THAT ARE UNDER THE
CLOUDS,AND CLOSER TO THE LAKE, WILL PROBABLY CLEAR OUT FASTER
THAN THE MID SECTIONS AS THE MIXING TAKES PLACE.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM EDT THU MAY 5 2016

OVERVIEW...THE 500 MB LOW THAT WAS IN OUR AREA YESTERDAY, IS NOW
IN THE OHIO VALLEY AND HAS TAKEN IT`S DEFORMATION AXIS WITH IT.
RADAR SHOWS NO RAIN IN THE REGION, WITH ONLY LOW AND MID LEVEL
CLOUDS FROM THE MOIST BOUNDARY LAYER AND THE MID LEVEL MOISTURE
ASSOCIATED WITH THE 500 MB LOW TO THE SOUTH. UPSTREAM, THERE IS A
500 MB SHORTWAVE TROUGH THAT IS DIVING SOUTH INTO THE UPPER
MISSISSIPPI VALLEY WITH SHOWERS AND CLOUDS ASSOCIATED WITH IT.

TODAY...AS THE 500 MB LOW MOVES TO THE SOUTH AND EAST THROUGH THE
DAY, DRIER AIR UPSTREAM WILL MOVE INTO THE AREA, AS HIGH PRESSURE
BUILDS INTO THE FORECAST AREA DURING THE DAY. THIS WILL ALLOW THE
SUN TO BEGIN TO MIX OUT THE MOISTURE, FROM THE RAIN YESTERDAY THAT
WAS TRAPPED OVERNIGHT AND FORMED THE LOW CLOUDS. MODELS SUGGEST THAT
WHILE THERE WILL BE DRYING IN THE MORNING, CONVECTIVE CU WILL
RESULT. THERE IS A POSSIBILITY THAT SPRINKLES COULD RESULT,
ALTHOUGH, THE BOUNDARY LAYER WILL BE FAIRLY DRY AS THE SFC RH IS
EXPECTED TO FALL TO AROUND 35% BY AFTERNOON. THE GFS HAS RAIN
THROUGH THE MIDDLE OF THE STATE, AND INTO NE LOWER, WHILE THE
ECMWF/NAM HAVE NOTHING.

TONIGHT...AS WE GET INTO THE EVENING THE INSTABILITY GOES AWAY AND
THE 850 MB DRY AXIS MOVE THROUGH THE STATE. THIS WILL ALLOW WHATEVER
CONVECTIVE CLOUDS THAT ARE AROUND TO DIMINISH. MID AND HIGH CLOUDS
MOVE IN WITH THE MOISTURE AT 700 MB AND IN THE 700-500 MB LAYER WITH
THE SHORTWAVE TROUGH (500 MB) THAT MOVING SOUTH INTO THE MID
MISSISSIPPI VALLEY. HOWEVER, 500 MB RIDGING IS TAKING PLACE OVER
E UPPER WHICH SHOULD THE REGION DRY.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 357 AM EDT THU MAY 5 2016

...WARM FRIDAY FOLLOWED BY RAIN FRIDAY NIGHT-EARLY SATURDAY...

HIGH IMPACT WEATHER POTENTIAL: MINIMAL.

PATTERN SYNOPSIS/FORECAST: SPLIT FULL-LATITUDE LONG WAVE TROUGH IN
PLACE ACROSS EASTERN NORTH AMERICA TO START THE POST-THURSDAY
FORECAST PERIOD...WITH A PAIR OF UPPER LOWS WITHIN THIS TROUGH WITH
ONE OVER THE MID ATLANTIC AND A MORE COMPACT VORTEX JUST SOUTH OF
BAFFIN ISLAND WITH A DEFORMATION AXIS IN BETWEEN THESE LOWS ACROSS
THE UPPER MIDWEST/NORTHERN ONTARIO.  MID ATLANTIC VORTEX PART OF A
NATIONWIDE BLOCKING PATTERN WITH ANOTHER LOW OVER SOUTHERN
CALIFORNIA AND A RIDGE IN BETWEEN THAT WILL BE FLATTENED OUT FRIDAY
BY SHORT WAVE ENERGY COMING OVER THE TOP ACROSS SASKATCHEWAN/
MANITOBA.  THESE HEIGHT FALLS ARE EXPECTED TO DIG SOUTHEAST INTO THE
UPPER LAKES SATURDAY AS BLOCKING TRANSITIONS FROM OMEGA TO A
WESTERN NORTH AMERICA REX BLOCK AS THE WEEKEND PROGRESSES.

WEAK HIGH PRESSURE RIDGE LYING ACROSS THE UPPER LAKES FRIDAY MORNING
WILL GET PUSHED SOUTH AS A COLD FRONT DROPS INTO MICHIGAN EARLY
SATURDAY...ACCOMPANIED BY COLD ADVECTION DURING THE DAY SATURDAY
AND A LINGERING DEEP LAYER THERMAL TROUGH SUNDAY.

PRIMARY FORECAST CONCERNS: PRECIPITATION/TEMPERATURES ASSOCIATED
WITH COLD FRONT/HEIGHT FALLS SATURDAY.

FRIDAY...WEAK HIGH PRESSURE RIDGE WILL LIE ACROSS LOWER MICHIGAN FOR
MUCH OF THE DAY FRIDAY...WHILE OUR APPROACHING COLD FRONT SLIPS INTO
THE UPPER MIDWEST.  ALSO SOME HINTS OF A LAKE-BREEZE ENHANCED WARM
FRONT ACROSS WESTERN UPPER/EASTERN WISCONSIN...WITH STEEP MID LEVEL
LAPSE RATES OVERSPREADING THE UPPER LAKES.  BOTH NAM-WRF/GFS TRYING
TO MOISTEN UP THE BOUNDARY LAYER ON THE OTHER SIDE OF LAKE MICHIGAN
AND GIN UP SOME INSTABILITY BUT THAT SEEMS TO BE A BIT DUBIOUS.  SO
A DRY AND WARM DAY EXPECTED FRIDAY...HIGHS AWAY FROM THE BEACHES
EXPECTED TO RANGE FROM THE UPPER 60S-MID 70S.  MARGINAL FIRE WEATHER
CONCERNS FOR FRIDAY ESPECIALLY IN LIGHT OF YESTERDAY`S RAINFALL
(THOUGH MOST OF THAT WAS "RIGHT DOWN THE MIDDLE" ALONG THE I-75
CORRIDOR)...MINIMUM RELATIVE HUMIDITY VALUES WILL PROBABLY DROP
TOWARD THE 25 PERCENT LEVEL WITH TEMPERATURES ALSO GETTING NEAR
CRITICAL VALUES.

COLD FRONT WILL DROP INTO LAKE SUPERIOR/UPPER MICHIGAN FRIDAY
EVENING...AND INTO NORTHERN LOWER AROUND DAYBREAK SATURDAY.  LOW
LEVEL THETA-E RIDGE LIES ALONG THE FRONT WITH SOME DECENT QG AND
RESULTANT FRONTOGENETIC FORCING ALONG THE BOUNDARY (ACTUALLY ALONG
THE SLOPED FRONTAL ZONE) ALONG WITH DIFLUENT FLOW AHEAD OF MAIN
HEIGHT FALLS.  COMBINED WITH ABOVE MENTIONED STEEP MID LEVEL LAPSE
RATES EXPECT AN INCREASED THREAT FOR SHOWERS AND SOME THUNDERSTORMS
AFTER MIDNIGHT SATURDAY.

SATURDAY...MOSTLY POST-FRONTAL BAND OF SHOWERS/EMBEDDED
THUNDERSTORMS WILL IMPACT MUCH OF THE FORECAST AREA SATURDAY
MORNING...BUT CURRENT INDICATIONS ARE THAT PRECIPITATION SHOULD MAKE
STEADY PROGRESS TO THE SOUTH AND SHOULD BE MOSTLY OUT OF THE AREA BY
MID SATURDAY AFTERNOON.  FORECAST TREND AT THIS POINT WILL BE TOWARD
MORE SUN FROM NORTHWEST TO SOUTHEAST THROUGHOUT THE DAY.  SHOULD
BECOME A LITTLE MORE BREEZY THROUGH THE DAY WITH INCREASING SUN/
MIXING AIDED BY LOW LEVEL COLD ADVECTION.  TEMPERATURES WILL
PROBABLY END UP NEAR AVERAGE WITH HIGHS MOSTLY IN THE 50S ACROSS
UPPER MICHIGAN AND UPPER 50S-MID 60S ACROSS NORTHERN LOWER. PASSING
SHORT WAVE TROUGH COULD BRING SOME MORE CLOUDS SATURDAY NIGHT
ESPECIALLY ACROSS EASTERN UPPER.  NOT CERTAIN IF MOIST LAYER WILL BE
DEEP ENOUGH TO SUPPORT PRECIP AND AT THIS POINT NOT INCLINED TO
CARRY ANY (ESCHEWING ANY SLIGHT CHANCE WORDING).  OTHERWISE LOOKING
QUIET AND COOL AS PRESSURE GRADIENT RELAXES WITH LOWS LIKELY
DIPPING INTO THE 30S WHERE SKIES CAN REMAIN CLEAR.

EXTENDED FORECAST (SUNDAY THROUGH FRIDAY)...DEVELOPING WESTERN REX
BLOCK AND AN UPPER LOW IN THE VICINITY OF JAMES BAY WILL FUNNEL A
COOLER AIR MASS INTO THE UPPER LAKES TO END THE WEEKEND...AND
MICHIGAN WILL PROBABLY REMAIN UNDER THE INFLUENCE OF THESE LOWER
HEIGHTS INTO MONDAY.  AIR MASS WILL MODERATE DURING THE FIRST HALF
OF THE WEEK...BUT WILL BE WATCHING THE SLOW-MOTION EASTWARD
PROGRESSION OF THE REMNANTS OF THE WESTERN REX BLOCK THAT WILL OPEN
UP AS IT MAKES IT WAY INTO THE NATION`S MIDSECTION DURING THE FIRST
HALF OF THE WEEK.  SUNDAY-MONDAY TIME FRAME LOOKS DRY...WITH A
BETTER CHANCE OF RAIN FROM MONDAY NIGHT THROUGH AT LEAST TUESDAY
NIGHT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 640 AM EDT THU MAY 5 2016

LOW CLOUDS OVER THE FORECAST AREA HAVE BEEN BUILDING UNDER
INVERSION THIS MORNING. HOWEVER, THINK THAT THE CLOUDS WILL START
ERODING BY 13Z WITH SOME OF THE REGION BEGINNING TO CLEAR OUT BY
14Z. IN THE NEAR TERM, PLN, WHICH IS CLEAR AT THIS POINT WILL
CLOUD OVER BRIEFLY AS A CLOUD MASS MOVES OVER THE TAF SITE THIS
MORNING, AND THEN WILL BE ERODED AS MIXING TAKES PLACE. APN, TVC
AND MBL ARE ALL UNDER THE CLOUDS NOW, BUT SINCE THEY ARE NEARER TO
THE CLOUD EDGE, WILL EXPECT THAT THEY WILL CLEAR OUT A LITTLE
FASTER THAN THE INTERIOR SECTIONS OF N LOWER.

OTHERWISE, VFR CONDITIONS WILL PREVAIL FROM ABOUT 16Z (AT THE
LEAST) UNTIL THE END OF THE TAF PERIOD.

&&

.MARINE...
ISSUED AT 357 AM EDT THU MAY 5 2016

TODAY THROUGH FRIDAY NIGHT...WINDS WILL CONTINUE TO DIMINISH THIS
MORNING AS THE SFC LOW MOVES OUT OF THE REGION, TAKING THE TIGHTENED
GRADIENT WITH IT. HIGH PRESSURE MOVES INTO THE REGION FOR THE DAY
AND WITH THE SLACK GRADIENT, AND WARMER TEMPERATURES, WILL EXPECT
THE LAKE BREEZES WILL BE PRESENT OVER ALL OF THE NEARSHORE AREAS.
TONIGHT, THE WINDS OVER LAKES MICHIGAN AND SUPERIOR WILL BEGIN TO
INCREASE AS GRADIENT TIGHTENS A BIT AS A SFC TROUGH MOVES INTO THE
UPPER GREAT LAKES IN ADVANCE OF THE NEXT SYSTEM. FRIDAY AND FRIDAY
NIGHT, AS THE NEXT SYSTEM MOVES INTO THE UPPER GREAT LAKES AND
THROUGH IT, THE WINDS WILL INCREASE A BIT MORE, BUT REMAIN BELOW
SMALL CRAFT CRITERIA. HOWEVER, IT LOOKS LIKE SATURDAY COULD BE A
SMALL CRAFT DAY AS THE WINDS ON THE BACK SIDE OF THE LOW INCREASE
FROM THE TIGHTENING GRADIENT, POSSIBLY EVEN LOW END GALES, IF WE CAN
MIX HIGH ENOUGH OVER THE LAKE.


&&

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

$$

UPDATE...JSL
SHORT TERM...JSL
LONG TERM...JPB
AVIATION...JSL
MARINE...JSL



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