Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 211018
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
618 AM EDT TUE OCT 21 2014

.SYNOPSIS...
ISSUED AT 350 AM EDT TUE OCT 21 2014

AS LOW PRESSURE PULLS FURTHER OFF TO THE SOUTHEAST TODAY...THE
DRIZZLE AND LIGHT RAIN WILL COME TO AN END. THIS WILL OPEN THE DOOR
FOR HIGH PRESSURE TO SET UP OVER THE GREAT LAKES...PROVIDING DRY
CONDITIONS AND A SLOW WARMING TREND INTO THE WEEKEND.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 350 AM EDT TUE OCT 21 2014

...IMPROVING WEATHER...

IMPACTS: NONE.

CURRENT WEATHER AND SYNOPTIC PATTERN:

LARGE SCALE AND DEEP UPPER TROUGHING IS DRIFTING ESE WITH HIGH
AMPLITUDE RIDGING STARTING TO BEND OVER INTO THE WESTERN GREAT
LAKES. AT THE SFC...LOW PRESSURE AND A COLD FRONT WAS WORKING TOWARD
THE MID ATLANTIC STATES...WHILE HIGH PRESSURE WAS SLOWLY TAKING HOLD
OF ONTARIO DOWN THROUGH LAKE SUPERIOR AND THE MISSISSIPPI VALLEY.
LOW LEVEL MOISTURE REMAINS DEEP...WITH INCREASING WARMING/SUBSIDENCE
ALOFT. STRATUS WAS WIDESPREAD WITH SOME CONTINUED LIGHT RAIN AND
DRIZZLE AT TIMES. THIS LIKELY BEING AIDED BY LAST SHORTWAVE/MID
LEVEL JET DROPPING THROUGH NRN MICHIGAN...ON THE BACKSIDE OF THE
UPPER TROUGH. TEMPERATURES WERE IN THE MIDDLE 40S.

SYNOPTIC PATTERN/WEATHER EVOLUTION:

PATTERN WILL BE SLOW TO CHANGE SINCE THE FINAL SHORTWAVE AND MID
LEVEL JET IS DIGGING INTO THE UPPER TROUGH AND DEEPENING THE UPPER
LOW. ALSO...MID LEVEL INCREASING HEIGHTS THROUGH ONTARIO WILL
EVENTUALLY HELP CLOSE THE SYSTEM OFF COMPLETELY...AND THE FILLING
PROCESS WILL BEGIN OVER THE EAST STATES. FOR NRN MICHIGAN...ITS A
RATHER LACKLUSTER WEATHER SCENARIO. IT`LL BE A BATTLE BETWEEN THE
SUBSIDENCE INVERSION/TRAPPING OF THE LOW LEVEL MOISTURE VS. LOW
LEVEL DRYING. LOOKING AT THE FCST BFR SOUNDINGS...THE SUGGESTION
WOULD BE FOR CLEARING SKIES BY LATE AFTERNOON. THIS IS IS PROBABLY
THE CASE IN EASTERN UPPER AND NW LOWER WHERE DOWNSLOPING AND DEEPER
DRIER AIR WILL RESIDE. HOWEVER...THERE IS STILL SOME RATHER
IMPRESSIVE SFC-925MB INSTABILITY IN NE WINDS THAT WILL MOST LIKELY
ADD MOISTURE UNDERNEATH THE INVERSION...PROBABLY MORE SO AT NIGHT
WHEN DIURNAL PROCESSES ARE GONE. THE LATTER OF WHICH MAY BE ENOUGH
TO AT LEAST POKE SOME HOLES INTO THE OVERCAST FOR THE AFTERNOON.
WOULD LOVE TO GO MORE OPTIMISTIC (MORE SUN) IN ALL AREAS...BUT
PATTERN SUGGESTS THAT CLOUDS MAY BE FINICKY TO DEPART ESPECIALLY IN
NE LOWER.

SLIGHT COLD ADVECTION AND AN EXPECTATION OF FAIRLY CLOUDY SKIES
THROUGH MID DAY OFFSETTING MINIMAL DIURNAL HEATING....LEAD TO FAIRLY
STEADY TEMPERATURES IN THE MIDDLE/UPPER 40S. LOWS TONIGHT ARE
DIFFICULT. IF CLOUDS ARE SLOW/HARD TO DEPART...MINIMAL DROP. IF WE
DO CLEAR...LIGHTER WINDS COULD MEAN CHILLY FOR SURE...WITH READINGS
IN THE MID AND UPPER 20S...WHICH IS THE CURRENT FORECAST. CONFIDENCE
IS NOT HIGH...BUT THE WARM ADVECTION ALOFT...IS JUST ABOVE THE CLOUD
LAYER WHICH WOULD SIGNAL ERODING CLOUDS. WITHIN THE CLOUD LAYER WE
HAVE NEAR NEUTRAL/SLIGHT COLD ADVECTION. GUT FEELING IS FOR MOSTLY
CLOUDY AND MORE STABLE TEMPS POSSIBLY HOLDING SEVERAL DEGREES ABOVE
GUIDANCE. ONLY DOWNSLOPING AREAS OF NW LOWER SEEING THE CLEARING AND
COLDER TEMPS. THE LIKELIEST SCENARIO...MAYBE SOME EARLY CLEARING
WITH REDEVELOPING CLOUDS TONIGHT. MUCH WILL RELY UPON WHAT HAPPENS
THIS AFTERNOON. THUS...WILL HOLD OFF ON ANY SIGNIFICANT CHANGES AND
LET THE DAY CREW ASSESS.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 350 AM EDT TUE OCT 21 2014

...QUIET WEEK WITH A AMBIGUOUS ENDING...

HIGH IMPACT WEATHER POTENTIAL: NONE

PRIMARY FORECAST CHALLENGES: HOW COLD DOES IT GET WEDNESDAY NIGHT
AND WHAT ABOUT THE RAIN STARTING LATE WEEKEND.

OVERVIEW...CURRENTLY IN A SLOWLY PROGRESSIVE PATTERN WITH A RIDGE
MID-CONUS AND 500 MB TROUGHS ON EITHER END OF THE CONTINENT. THE
IDEA WILL BE THAT THE 500 MB SHORTWAVE TROUGHS WILL MOVE THROUGH THE
RIDGE THROUGH THE WEEK, FLATTENING IT BEFORE THE NEXT ROUND OF
RIDGING WORKS IN FOR THE WEEKEND, ONLY TO BE FLATTENED BY MONDAY.
THE QUESTION WILL BE WHETHER THE SHORTWAVE THAT MOVES INTO THE
MIDWEST/UPPER GREAT LAKES DIGS ENOUGH TO PUSH THE RAIN INTO
MICHIGAN.

(10/22)WEDNESDAY...HIGH PRESSURE AT THE SFC AND UP TO 500 MB KEEPS
TE DRY AIR ENTRENCHED IN THE UPPER GREAT LAKES AND PUSHES THE CLOUDS
FROM THE STACKED LOW IN THE EAST OFF THE ATLANTIC COAST. SO DRY
WEATHER, AND MOSTLY SUNNY SKIES.

WEDNESDAY NIGHT...THE CLEAR SKIES AND CALM WINDS AS THE CORE OF THE
SFC RIDGE SITS OVER THE FORECAST AREA. MET/MAV NUMBERS END UP IN THE
LOWER TO MID 30S. THINK THAT AS WE ARE HEADING INTO END OF THE MONTH
AND THAT GOING BELOW NORMAL (NORMAL LOW AT GLR IS 34) IS A GOOD BET
AS THE WINDS GO CALM AND THE SKIES REMAIN CLEAR, THAT WE WILL
RADIATE AWAY THE HEAT. HAVE MID TO UPPER 20S IN THE INTERIOR OF THE
STATE WITH THE LAKE SHORE TEMPERATURES AROUND 30.

(10/23)THURSDAY...THE HIGH PRESSURE REMAINS OVER THE REGION AT THE
SFC WITH THE NEXT 500 MB SHORTWAVE TROUGH PUSHING INTO THE BOUNDARY
WATERS REGION. THE RIBBON OF MOISTURE ALONG THIS TROUGH LOOKS RATHER
THIN, SO THINK THAT THE MODEL TREND OF THIS FEATURE GETTING
STRETCHED AND LITTLE TO NO PRECIPITATION BEING PRODUCED THROUGH THE
NIGHT IS THE CORRECT WAY TO GO.

EXTENDED (FRIDAY THROUGH MONDAY)...(10/24)FRIDAY...THE MODELS SPLIT
THE 500 MB FLOW OVER THE REGION AND SHUNT THE MOISTURE SOUTH, WHICH
RESULTS IN PRECIPITATION FREE WEATHER FOR THE DAY.
(10/25)SATURDAY...500 MB HEIGHTS BUILD INTO THE UPPER GREAT LAKES AS
HIGH PRESSURE BEGINS TO MOVE INTO THE STATE. DRY WEATHER.
(10/26)SUNDAY...HERE`S WHERE THE MODELS BEGIN TO DIFFER. THE GFS
BRINGS A 500 MB SPEED MAX WITH THE DEVELOPING WARM FRONT WITH WHAT
SEEMS TO BE ONLY LOW LEVEL (850 MB AND BELOW) MOISTURE. THE ECMWF
HAS THE LOW LEVEL MOISTURE FARTHER WEST CLOSER TO THE SFC LOW. THERE
IS ALMOST NO MOISTURE ABOVE 850 MB. SO WILL KEEP THE DAY DRY. IT
LOOKS LIKE THE 700-500 MB LAYER RH BEGINS TO INCREASE TO ABOVE 60%
SO THINK THAT RAIN COULD BEGIN TO DEVELOP, HOWEVER, THE GFS KEEPS
DEVELOPING THE RAIN UNDER THE DRIER 700-500 MB LAYER RH AREAS. SO
WILL LEAN TOWARD THE ECMWF IDEA AND HAVE THE CHANCE POPS IN C/E
UPPER. (10/27)MONDAY...AS THE 500 MB SHORTWAVE TROUGH BEGINS TO DIG
AND THE SFC LOW DEVELOPS, THE QUESTION IS NOW THE AMOUNT OF
DEVELOPMENT, WHICH WILL HELP TO DETERMINE THE STORM TRACK. THE WEAK
GFS SFC LOW WOULD PUSH OVER N LOWER. THE STRONG ECMWF STORM WOULD
TRACK WEST. TRIED A BEST GUESS AND PUT THE RAIN MORE TOWARD THE
NORTH/WEST ECMWF TRACK WITH SOME POPS FOR THE SOUTH/EAST GFS TRACK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 614 AM EDT TUE OCT 21 2014

...MVFR CIGS TRENDING TO MORE SUN IN NW LOWER...

PRETTY SOLID MVFR CIGS OUT THERE...BUT THERE IS SOME RAPID CLEARING
FROM THE NORTH...DUE TO DRY AIR ADVECTION. COULD SEE PLN CLEARING
OVER THE NEXT COUPLE OF HOURS...WITH SCATTERED CIGS AT TVC/MBL
LATER THIS MORNING. A GUSTY NE FLOW OFF LAKE HURON AND OVERLAKE
INSTABILITY WILL LIKELY KEEP SKIES GENERALLY MOSTLY CLOUDY WITH
MVFR AT APN THROUGH THE DAY...WITH MAYBE SOME SCATTERING OUT LATE
THIS AFTERNOON AND INTO THE EVENING. THE MVFR COULD EASILY COME
BACK IN LATER TONIGHT AFTER DIURNAL PROCESSES HAVE ENDED...WITH
LOW LEVEL MOISTURE OFF LAKE HURON GETTING CAUGHT UNDER AN
INVERSION.

&&

.MARINE...
ISSUED AT 350 AM EDT TUE OCT 21 2014

...GUSTY ADVISORY LEVEL WINDS TO SETTLE DOWN...

SMALL CRAFT ADVISORY GUSTS STILL EXPECTED TO CONTINUE THROUGH A GOOD
CHUNK OF TODAY...AND POSSIBLY THIS EVENING FOR NEARSHORE WATERS
SOUTH OF PRESQUE ISLE LIGHT...BEFORE HIGHER PRESSURE GRADUALLY
SETTLES IN. WILL KEEP THE ADVISORY GOING TODAY AND NOT PUSH THE
ADVISORY INTO THIS EVENING YET FOR ANY NEARSHORES. WINDS AND WAVES
BECOME LITTLE ISSUE THROUGH THE REMAINDER OF THE WORK WEEK.

SOME PATCHY DRIZZLE WILL END THIS MORNING...WITH NO PRECIPITATION
EXPECTED THE REMAINDER OF THE WEEK.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LHZ345-
     347>349.
LM...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LMZ323-342-
     344>346.
LS...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR LSZ321.

&&

$$

SYNOPSIS...JL
SHORT TERM...SMD
LONG TERM...JL
AVIATION...SMD
MARINE...SMD






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