Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 190345
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1145 PM EDT THU SEP 18 2014

.SYNOPSIS...
ISSUED AT 358 PM EDT THU SEP 18 2014

MODERATING TEMPERATURES ARE EXPECTED FRIDAY INTO SATURDAY DUE TO A
WARMER SOUTHWESTERLY WIND FLOW AHEAD OF A DEVELOPING LOW PRESSURE
SYSTEM OVER THE NORTHERN PLAINS. SHOWERS AND CHANCES FOR
THUNDERSTORMS BEGIN FRIDAY NIGHT...AND CONTINUE THROUGH SATURDAY
EVENING AS THE STORM SYSTEM REACHES THE GREAT LAKES REGION...WITH
SHOWERS POSSIBLY LINGERING INTO SUNDAY AS WELL.

&&

.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 358 PM EDT THU SEP 18 2014

BIG HIGH PRESSURE CENTER JUST NNE OF KANJ THIS AFTERNOON RESULTING
IN OVERALL QUIET WEATHER. MORNING STRATUS DECK HAS MIXED/ERODED TO A
DECENT EXTENT ACROSS THE CWA...SAVE FOR THE FAR E/SE PARTS OF NRN
LOWER MICHIGAN. SHORT TERM FORECAST ISSUE REVOLVES AROUND CLOUD
COVER TONIGHT AND FROST POTENTIAL.

TONIGHT...HIGH PRESSURE CENTER SLIDES ON TO THE EAST WITH LOW
LEVEL FLOW VEERING AROUND TO THE SOUTH BY FRIDAY MORNING. DESPITE
TODAYS MIXING AND CLEARING TRENDS...WITH BOUNDARY LAYER COOLING
TONIGHT STILL BELIEVE THAT LEFTOVER LOW LEVEL MOISTURE LAYER
SITTING ACROSS LOWER MICHIGAN INTO WISCONSIN WILL SIMPLY GET
RECYCLED BACK NORTHWARD AND POTENTIALLY BRING ANOTHER BATCH OF
EXPANDING STRATUS UP THROUGH NRN LOWER/EASTERN UPPER MICHIGAN...LATE
THIS EVENING AND OVERNIGHT. NAM/RUC/GFS 925 MB RH FORECASTS CONTINUE
TO SUGGEST THAT IDEA. OF COURSE THAT WOULD BE A LIMITING FACTOR TO
FROST DEVELOPMENT/LONGEVITY.

STILL...A TOUGH CALL ON TEMPS/FROST AS ANY FROST/FREEZE HEADLINES
REALLY NEED TO BE ISSUED BEFORE TO LATE IN THE DAY (FROST ADVISORY
AT 11 PM IS REALLY NOT THAT HELPFUL). IF IT DOES NOT CLOUD BACK
UP...SOME OF THE COLD INLAND AREAS WILL BE SITTING AT 28 DEGREES
TOMORROW MORNING. FOR NOW...AM BANKING ON THE CLOUDS AND WILL
JUST KEEP THE MENTION OF FROST IN THE FORECAST FOR MUCH OF NE
LOWER MICHIGAN AND PARTS OF EASTERN UPPER MICHIGAN WHERE I THINK
SKIES WILL REMAIN CLEAR THE LONGEST. BUT WILL REFRAIN FROM A FROST
ADVISORY.

.LONG TERM...(FRIDAY THROUGH THURSDAY)
ISSUED AT 358 PM EDT THU SEP 18 2014

...BECOMING BREEZY AND WARMER FRIDAY...
...AN INCREASING RISK FOR SHOWERS AND THUNDERSTORMS FRIDAY NIGHT...

HIGH IMPACT WEATHER POTENTIAL AND PRIMARY FORECAST CHALLENGES: WINDS
WILL INCREASE LATE FRIDAY INTO SATURDAY...POSSIBLY RESULTING IN
GALES ON PARTS OF THE GREAT LAKES. IN ADDITION...WILL ASSESS
THUNDERSTORM THREAT FOR FRIDAY NIGHT AND SATURDAY...INCLUDING SEVERE
POTENTIAL.

FRIDAY: HIGH PRESSURE WILL BE OVER SRN QUEBEC EARLY FRIDAY...AND
WILL RESULT IN INCREASING SOUTHERLY FLOW DURING THE DAY AS THE
SURFACE PRESSURE GRADIENT TIGHTENS IN ADVANCE OF STORM SYSTEM
APPROACHING FOR FRIDAY NIGHT AND SATURDAY. THOUGH OVERALL AIRMASS
WILL BE RELATIVELY DRY /H8-H5 RH INITIALLY 25-40%/ CONCERN REMAINS
THAT LOW LEVEL MOISTURE WILL LINGER EARLY - IN ABSENCE OF STRONG DRY
AIR ADVECTION AND/OR DEEP MIXING THURSDAY (NOT UNLIKE CLOUD PATTERN
CURRENTLY OVER WI). FORECAST WILL REFLECT ADDITIONAL CLOUDS EARLY
/MAINLY ACROSS NRN LOWER/ WITH WARMING AND MIXING QUICKLY LEADING TO
GREATER SUN BY MID-LATE MORNING AND THROUGH THE AFTERNOON. HIGHS
WILL PEAK IN THE 60S.

FRIDAY NIGHT AND SATURDAY: JET STREAK OVER SOUTHERN BRITISH COLUMBIA
AND ALBERTA EARLY FRIDAY WILL RACE ESEWD...AND RESULT IN HEIGHT
FALLS AND UPPER FLOW AMPLIFICATION OVER THE UPPER MS VALLEY AND WRN
GREAT LAKES BY SATURDAY. AN ASSOCIATED SURFACE FRONT WILL ADVANCE
INTO THE UPPER MS VALLEY FRIDAY NIGHT AND EVENTUALLY INTO THE GREAT
LAKES SATURDAY. STRONG H8 SW FLOW AHEAD OF SYSTEM />45 KTS/ WILL
ADVECT ENHANCED MOISTURE INTO THE REGION /WITH H8 DEW POINTS NEARING
+15C BY SATURDAY MORNING/. EXPECT SHOWERS/STORMS TO DEVELOP FROM THE
CENTRAL U.P. TO WRN WI FRIDAY AFTERNOON/EVENING...AND THEN MOVE EWD
INTO ERN UPPER AND NW LOWER FRIDAY NIGHT. LACK OF APPRECIABLE
INSTABILITY AT THE SURFACE OR ALOFT...SUGGESTS SEVERE THREAT WILL BE
LOW. THE SEVERE THREAT FOR SATURDAY APPEARS HIGHER - THOUGH NOT A
SLAM DUNK BY ANY STRETCH. WITH CONVECTIVE DEBRIS AND/OR ONGOING
NON-SEVERE CONVECTION EARLY SATURDAY...DESTABILIZATION WILL AS USUAL
BE AN ISSUE (NOT TO MENTION IMPACT OF A PROGRESSIVELY LOWER
SEPTEMBER SUN ANGLE). HOWEVER...NAM SUGGESTS POTENTIAL FOR >1K J/KG
MLCAPE MIDDAY OVER NRN LOWER...WITH DEEP/STRONG QUASI-UNIDIRECTIONAL
SW FLOW (H8 WINDS AROUND 40 KTS...AND H5 WINDS AROUND 50 KTS). IF
INSTABILITY CAN BE REALIZED...ANY STORMS THAT DEVELOP COULD BE WIND
PRODUCERS. OTHERWISE...LOOK FOR A GOOD THREAT FOR SHOWERS/STORMS
AREA WIDE AS COLD FRONT CONTINUES TO MOVE INTO THE AREA...WITH HIGHS
PEAKING IN THE 60S TO LOWER 70S.

SATURDAY NIGHT AND SUNDAY...GENERALLY UNSETTLED WEATHER WILL
PERSIST. AS AFOREMENTIONED COLD FRONT HEADS EAST OF REGION...TROUGH
ALOFT WILL CONTINUE TO AMPLIFY OVER THE GREAT LAKES AS SHORT WAVE
ROTATES EWD. WITH CYCLONIC FLOW AND A SECONDARY SURFACE TROUGH
IMPACTING NRN MI...THERE WILL BE A CONTINUE RISK FOR SHOWERS
SATURDAY NIGHT AND SUNDAY - WITH THE BEST CHANCE SATURDAY NIGHT WILL
MAIN COLD FRONT STILL EXITING REGION. WILL RETAIN SMALL RISK FOR
THUNDER THROUGH SATURDAY EVENING. LOWS SATURDAY NIGHT WILL DIP INTO
THE UPPER 40S TO MID 50S...WITH HIGHS ON SUNDAY IN UPPER 50S TO MID
60S.

REMAINDER OF FORECAST /MONDAY THROUGH THURSDAY/...GFS/ECMWF ARE IN
GOOD AGREEMENT THAT THIS WEEKENDS STORM SYSTEM WILL RESULT IN HIGH
AMPLITUDE FLOW FOR THE START OF NEXT WEEK...AND FEATURE DEEP
TROUGHING OVER NE QUADRANT OF THE CONUS WITH UPSTREAM RIDGING WEST.
THIS UPPER TROUGH IS PROGGED TO EJECT/LIFT ENEWD AS BROAD UPPER
LEVEL RIDGING EXPANDS ACROSS THE NRN CONUS AND EVENTUALLY INTO THE
GREAT LAKES BY WEDNESDAY AND THURSDAY. FOR NRN MICHIGAN...THIS WILL
LIKELY LEAD TO SEASONABLY COOLISH TEMPERATURES AND A SMALL RISK FOR
SHOWERS IN THE MONDAY-TUESDAY TIMEFRAME...WITH DRY AND WARMER
WEATHER BY MIDWEEK. AS USUAL...SOME UNCERTAINTIES EXIST REGARDING
TIMING/STRENGTH OF THE LAST SHORT WAVE FORECAST TO DROP INTO MEAN
UPPER TROUGH BEFORE IN EXITS /THE LATEST GFS IS A BIT STRONGER THAN
ECMWF/. GREATER RUN-TO-RUN CONSISTENCY WITH THE ECMWF...AND GFS RUNS
THAT ARE TRENDING WEAKER...WOULD TEND TO SUPPORT SOMEWHAT WEAKER
ECMWF. HIGHS INITIALLY IN THE 50S TO AROUND 60 MONDAY WILL MODERATE
INTO THE 60S TO LOWER 70S BY WEDNESDAY-THURSDAY.

MODELS STRONGLY SUGGEST THE MIDWEEK WARMUP WILL BE THE START OF A
CONTINUED WARMING TREND POTENTIALLY EXTENDING WELL INTO NEXT WEEKEND
(AND BEYOND?). THAT SAID...LONGER RANGE MODEL GUIDANCE DURING
TRANSITION SEASONS ARE NOTORIOUS FOR EXHIBITING POOR CONSISTENCY
FROM RUN-TO-RUN. STAY TUNED.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1145 PM EDT THU SEP 18 2014

LOW CLOUDS WILL AGAIN INCREASE OVERNIGHT AS LOW LEVEL FLOW TURNS
SOUTHERLY...PUSHING LOW LEVEL MOISTURE BACK INTO NRN LWR MICHIGAN.
CIGS WILL DROP TO MVFR OVERNIGHT INTO EARLY FRIDAY...BUT EXPECT
LOW CLOUDS WILL MIX OUT BY LATE MORNING THANKS TO STRENGTHENING
SOUTHERLY FLOW ON THE BACK SIDE OF DEPARTING HIGH PRESSURE. LOW
CLOUDS WILL AGAIN INCREASE TOWARD FRIDAY EVENING AS WIDESPREAD
RAIN SHOWERS DEVELOP BY MID TO LATE EVENING AHEAD OF A COLD FRONT
SLIDING INTO THE WRN GREAT LAKES REGION. THERE IS A SMALL CHANCE
OF THUNDER...BUT MAINLY AFTER 06Z SATURDAY. LIGHT/VARIABLE SURFACE
WINDS TONIGHT WILL BECOME SOUTH AT AROUND 10 KTS ON FRIDAY.

&&

.MARINE...
ISSUED AT 358 PM EDT THU SEP 18 2014

LIGHT WINDS WILL BE FOUND ACROSS THE GREAT LAKES TONIGHT. SOUTHERLY
WINDS INCREASE FRIDAY THROUGH FRIDAY NIGHT IN ADVANCE OF A COLD
FRONT THAT WILL SWING THROUGH THE REGION SATURDAY. SMALL CRAFT
ADVISORIES ARE A GOOD BET FOR FRIDAY AND FRIDAY NIGHT FOR ALL
NEARSHORE AREAS. SOME GUSTS GETTING TO AROUND GALE FORCE ARE ALSO
POSSIBLE ON LAKE MICHIGAN FRIDAY NIGHT AND WILL HOIST A GALE WATCH
ACCORDINGLY.

WINDS DIMINISH A BIT SATURDAY AND VEER NORTHWEST SATURDAY NIGHT.
SMALL CRAFT ADVISORY CONDITIONS MAY PERSIST INTO SATURDAY FOR
PARTS OF THE GREAT LAKES BUT FALL OFF SATURDAY NIGHT.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...GALE WATCH FROM FRIDAY AFTERNOON THROUGH SATURDAY MORNING FOR
     LMZ341-342-344>346.
LS...NONE.

&&

$$

SYNOPSIS...TL
SHORT TERM...ADAM
LONG TERM...BS
AVIATION...MR
MARINE...ADAM






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