Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 302300
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
700 PM EDT TUE SEP 30 2014

.SYNOPSIS...
ISSUED AT 354 PM EDT TUE SEP 30 2014

WEDNESDAY WILL SEE MILD AND DRY WEATHER...HOWEVER...ANOTHER STORM
SYSTEM WILL BRING POTENTIALLY SIGNIFICANT RAINFALL FOR THURSDAY AND
THURSDAY NIGHT. PERIODS OF WET WEATHER WILL LAST THROUGH THE
WEEKEND...WITH A RETURN TO COOL TEMPERATURES.

&&

.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 354 PM EDT TUE SEP 30 2014

HIGH IMPACT WEATHER POTENTIAL:  NONE.

FORECAST CHALLENGES:  DRIZZLE POTENTIAL AND CLOUD TRENDS.

TONIGHT:  LARGE EXPANSE OF LOW LEVEL MOISTURE WILL CONTINUE TO BE
LOCKED BENEATH STRENGTHENING 900MB INVERSION ACROSS THE NORTHERN
LAKES...RESULTING IN STRATUS/DRIZZLE/FOG ISSUES ONCE AGAIN.  ANY
BREAKS IN THE OVERCAST THIS EVENING WILL BE SHORT LIVED...AS LOW
LEVEL FLOW VEERS SOUTHEASTERLY OVERNIGHT AND STRATUS EXPANDS TO THE
NORTH-WEST.  PLENTY OF SIGNS POINTING TOWARD DRIZZLE/FOG DEVELOPMENT
ONCE AGAIN WITH SPECIFIC HUMIDITY INCREASING WITH HEIGHT WITH WARM
AIR ADVECTION AT THE LOW LEVELS.  WILL NOT TRY TO GET TOO SPECIFIC
TRYING TO PINPOINT WHAT AREAS WILL SEE DRIZZLE....ALTHOUGH BEST
CHANCES APPEAR TO BE OVER THE EASTERN 2/3 OF THE AREA WHERE THE
DEEPEST H9-H8 MOISTURE WILL RESIDE.  LITTLE RANGE IN TEMPERATURES
WITH READINGS GENERALLY IN THE LOWER-MIDDLE 40S.

.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
ISSUED AT 354 PM EDT TUE SEP 30 2014

...LOOKING VERY UNSETTLED TO END THE WEEK...

HIGH IMPACT WEATHER POTENTIAL: SOME HEAVIER RAINFALL THURSDAY
THROUGH FRIDAY (IN EXCESS OF 1.50 INCHES POSSIBLE).

PATTERN SYNOPSIS/FORECAST: CURRENT LARGE SCALE PATTERN FEATURES
SPLIT FLOW ORIGINATING FROM A QUASI-REX BLOCK JUST EAST OF THE
DATELINE AND CONTINUING DOWNSTREAM WITH AN AMPLIFIED PATTERN ACROSS
NORTH AMERICA.  SOUTHERN BRANCH FLOW EMANATING AROUND THE LOW
PRESSURE PORTION OF THIS BLOCK IS THE PREDOMINANT STREAM IMPACTING
THE CONTINENTAL U.S...WITH NORTHERN BRANCH FLOW DISPLACED NORTH
ACROSS CANADA.  SHORT WAVE TROUGH MOVING THROUGH THE LOWER GREAT
LAKES THIS AFTERNOON (WHICH HAS BROUGHT OUR RECENT WARM/DRY SPELL TO
A CRASHING HALT OVER THE PAST 24 HOURS)... WITH A NARROW SHORT WAVE
RIDGE ACROSS THE MISSISSIPPI VALLEY AHEAD OF ANOTHER PIECE OF ENERGY
OVER THE HIGH PLAINS AND A SECOND DIGGING SOUTHEAST ACROSS THE
PACIFIC NORTHWEST.  AT THE SURFACE...HIGH PRESSURE WAS BUILDING
ACROSS THE UPPER MISSISSIPPI VALLEY/UPPER GREAT LAKES BEHIND
YESTERDAY`S COLD FRONT PASSAGE.  THIS FRONT NOW MOVING ACROSS THE
LOWER LAKES EXTENDS BACK TO THE WEST AND INTO THE CENTRAL PLAINS
ATTACHED TO A SURFACE LOW OVER WESTERN SOUTH DAKOTA.  RETURN FLOW
MOISTURE WAS FUNNELING NORTH AHEAD OF THIS SURFACE LOW AND
ASSOCIATED UPPER LEVEL WAVE...WHILE DRY AIR ALOFT SPREADS ACROSS THE
UPPER LAKES ON DEEP LAYER NORTH/NORTHEAST FLOW.

UPSTREAM SHORT WAVE ENERGY WILL CARVE OUT A MORE ORGANIZED TROUGH
ACROSS WESTERN NORTH AMERICA...WITH THE UPPER LAKES ON THE EASTERN
FRINGES OF THIS TROUGH THROUGH MIDWEEK.  A REINFORCING JET STREAK
EMANATING FROM THE NORTHERN BRANCH FLOW NEAR ALASKA DIGS INTO THIS
TROUGH THURSDAY...PUSHING HEIGHT FALLS INTO THE REGION AND LEADS TO
DEVELOPMENT OF A STRONG CLOSED LOW OVER THE UPPER MISSISSIPPI VALLEY
BY FRIDAY.  THE IMPACTS OF THIS LOW/TROUGH WILL BE FELT THROUGH THE
WEEKEND.  THE APPROACHING HEIGHT FALLS THURSDAY WILL PUSH A COLD
FRONT ACROSS THE MIDWEST...LIKELY CROSSING THE FORECAST AREA FRIDAY
MORNING.  MOISTURE EXPECTED TO SURGE NORTH AHEAD OF THIS FRONT
THURSDAY INTO THURSDAY NIGHT...WITH STRONG COLD ADVECTION AND LIKELY
BRISK CONDITIONS BEHIND THE FRONT BY FRIDAY AFTERNOON.

PRIMARY FORECAST CONCERNS (NEAR TERM): THE INCREASING PRECIPITATION
THREAT AND POTENTIAL RAINFALL AMOUNTS THURSDAY/THURSDAY NIGHT...AND
TEMPERATURE/WIND TRENDS FRIDAY ALONG WITH THE IMPACTS OF INCREASING
OVER WATER INSTABILITY.

NEAR TERM (WEDNESDAY/THURSDAY): ANTICIPATE THAT WEDNESDAY WILL DAWN
CLOUDY AND SOMEWHAT DRIZZLY WITH LOTS OF TRAPPED MOISTURE/SHALLOW
WARM ADVECTION/SOUTHEAST UPSLOPE BOUNDARY LAYER FLOW INTO THE HIGHER
TERRAIN.  MAY BE A LITTLE BETTER CHANCE TO MIX OUT INTO SOME SUN
WEDNESDAY AFTERNOON AS STRATUS LIFTS INTO A CUMULUS/STRATOCUMULUS
DECK...BUT EXPECT THIS TO BE A SLOW PROCESS.  COLD FRONT EXPECTED TO
PUSH ACROSS THE MIDWEST WEDNESDAY NIGHT...WITH A SURGE OF MOISTURE
AHEAD OF IT (PRECIPITABLE WATER AT OR ABOVE 1.50 INCHES...2-3
STANDARD DEVIATIONS ABOVE THE MEAN FOR EARLY OCTOBER).  BAND OF
SHOWERS AHEAD OF THIS FRONT WILL PUSH TOWARD WESTERN PORTIONS OF THE
FORECAST AREA BY THURSDAY MORNING...THOUGH THE MAIN PRECIPITATION
EVENT EXPECTED TO OCCUR THURSDAY.  SOME FOG POSSIBLE WEDNESDAY NIGHT
ESPECIALLY IF MIXING IS LIMITED DURING THE DAY.

INITIAL PUSH OF WARM ADVECTION PRECIPITATION WILL ARRIVE THURSDAY
MORNING...APPEARS THAT SATURATION WILL BE OCCURRING FROM THE TOP
DOWN SO WILL TAKE SOME TIME TO MOISTEN LOWER LAYER SUFFICIENTLY FOR
PRECIPITATION TO OCCUR.  THIS PROBABLY MEANS THAT PRECIPITATION
HOLDS OFF ACROSS NORTHEAST LOWER UNTIL THURSDAY AFTERNOON...AND
HEAVIEST RAINFALL DURING THE DAY THURSDAY EXPECTED ACROSS EASTERN
UPPER/NORTHWEST LOWER.  A FRONTAL WAVE DEVELOPING ALONG THE
APPROACHING COLD FRONT THURSDAY NIGHT IS EXPECTED TO LIFT NORTH
ACROSS WISCONSIN AND LAKE SUPERIOR BY FRIDAY MORNING...WITH THE COLD
FRONT ITSELF EXPECTED TO BE ON OUR DOORSTEP BY DAYBREAK FRIDAY.
THURSDAY NIGHT WILL LIKELY BE THE PERIOD OF HEAVIEST RAINFALL AS
FORCING ALONG FRONTAL CIRCULATION AND SOME ENTRANCE REGION JET
DYNAMICS AND HEIGHT FALLS HELP SQUEEZE OUT THE PRECIPITATION
(DECREASING STABILITY WON`T HURT...MAY BE OUR BEST CHANCE TO HEAR
SOME THUNDER OUT OF THIS EVENT).  STILL LIKE THE IDEA OF 1-2 INCHES
OF RAIN ALONG-WEST OF THE I-75 CORRIDOR THURSDAY/THURSDAY NIGHT...AN
IDEA SUPPORTED BY ANALOGS AS WELL.

MEDIUM RANGE (FRIDAY/SATURDAY/SUNDAY): SHOWERS WILL CONTINUE INTO
FRIDAY AS COLD FRONT TRAVERSES LOWER MICHIGAN...WOULD SUSPECT WE`LL
ALSO SEE TEMPERATURES DROP DURING THE AFTERNOON AS COLDER AIR SWEEPS
IN AND WILL HAVE SOME SEMBLANCE OF THAT IN HOURLY TEMPERATURE GRIDS
FOR FRIDAY.  WINDS FRIDAY WILL DEPEND ON EVOLUTION OF SURFACE LOW
LIFTING INTO ONTARIO AND HAVE SOME UNCERTAINTY REGARDING THOSE
DETAILS. WEEKEND LOOKING COOL AND UNSETTLED WITH COOL AIR
CROSSING THE GREAT LAKES AND PLENTY OF CYCLONIC FLOW. EXPECT
TEMPERATURES ARE GOING TO HAVE A HARD TIME GETTING OUT OF THE 40S
SATURDAY AND SUNDAY.

OUTLOOK (MONDAY/TUESDAY): PLAN TO KEEP THINGS COOL AND SHOWERY INTO
THE FIRST PART OF THE WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 700 PM EDT TUE SEP 30 2014

MVFR/OCCASIONAL IFR CIGS WILL HANG OVER ALL NRN LWR MICHIGAN TAF
SITES TONIGHT THRU WEDNESDAY...ALTHOUGH WE MAY SEE SOME
IMPROVEMENT TOWARD WEDNESDAY EVENING. VFR VSBYS WILL DIMINISH TO
MVFR/IFR LATE TONIGHT INTO EARLY WEDNESDAY AS AREAS OF FOG
DEVELOP. ANY FOG THAT DOES DEVELOP WILL DISSIPATE BY MID TO LATE
WEDNESDAY MORNING. LIGHT/VARIABLE WINDS TONIGHT WILL BECOME E/SE
AOB 10 KTS ON WEDNESDAY.

&&

.MARINE...
ISSUED AT 354 PM EDT TUE SEP 30 2014

WINDS EXPECTED TO SWING AROUND FROM NORTHERLY TO SOUTHEAST ON
WEDNESDAY AS HIGH PRESSURE PULLS AWAY FROM THE UPPER GREAT LAKES.
WINDS EXPECTED TO BE RELATIVELY LIGHT EXCEPT OVER FAR NORTHERN LAKE
HURON NEARSHORE ZONES AS WINDS FUNNEL INTO THE STRAITS REGION
(AROUND 15KTS).  SOUTH/SOUTHEAST WINDS WILL CONTINUE INTO
THURSDAY...AND WILL INCREASE THROUGH THURSDAY AFTERNOON INTO
THURSDAY NIGHT AS GRADIENT TIGHTENS AS A FRONTAL WAVE LIFTS NORTH
ALONG A COLD FRONT SLOWLY MOVING INTO THE UPPER GREAT LAKES.  THIS
MAY NECESSITATE SMALL CRAFT ADVISORIES.  WINDS WILL VEER TO A MORE
WESTERLY COMPONENT FRIDAY WITH COLD FRONT PASSAGE.

&&

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

&&

$$

SYNOPSIS...AM
SHORT TERM...JK
LONG TERM...JPB
AVIATION...MR
MARINE...JPB






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