Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 270244
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
944 PM EST FRI DEC 26 2014

.UPDATE...
ISSUED AT 944 PM EST FRI DEC 26 2014

GIVEN SURFACE TEMP TRENDS...AND EXPECTATIONS FOR THE REMAINDER OF
THE NIGHT...HAVE REMOVED MENTION OF SNOW FROM A GOOD PORTION OF
NORTHERN LOWER. SHORT-TERM MODEL GUIDANCE DOING A POOR JOB OF
PORTRAYING THE MILD/MOIST AIRMASS IN PLACE...WITH TEMPS IN THE
UPPER 30S TO AROUND 40F IN NW LOWER MI (COOLER IN THE SOUTH WHERE
PARTIAL CLEARING HAS OCCURRED). HAVE ALSO REDUCED POPS A BIT IN
NORTHERN LOWER...AS DYNAMICS IN THE WARM SECTOR LOOK TO BE QUITE
UNIMPRESSIVE. AN EVENTUAL DRIZZLY RAIN SEEMS REASONABLE...BUT THAT
COULD WELL WAIT UNTIL ALMOST DAWN ACROSS MUCH OF NORTHERN LOWER.

UPDATE ISSUED AT 842 PM EST FRI DEC 26 2014

TEMPERATURES HAVE RISEN ABOVE FREEZING IN EASTERN UPPER MI...WITH
PARTS OF FAR WESTERN CHIP/MACK A POSSIBLE EXCEPTION (ERY STILL
32F). HAVE MINIMIZED FZDZ MENTION THERE...AND REMOVED MENTION FROM
THE HAZ WX OUTLOOK.

LIKE LAST NIGHT...PARTIAL CLEARING IN CENTRAL LOWER MI IS EDGING
UP INTO SOUTHERN PORTIONS OF THE FORECAST AREA. HAVE REDUCED CLOUD
COVER IN SOUTHERN SECTIONS...AND HAVE EXPANDED A MENTION OF FOG
FOR THE SAME (MT PLEASANT ALREADY LESS THAN 1SM).

&&

.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 347 PM EST FRI DEC 26 2014

CURRENT SFC OBS AND SATELLITE DATA SHOWING SOME BREAKS IN THE CLOUDS
ACROSS NRN LOWER WHILE AREA OF LOW CLD AND PATCHY DRIZZLE LINGERS
ACRS THE STRAITS AND ERN UPPER MICHIGAN.

NEARLY STAGNANT PATTERN TO CONTINUE OVER THE GREAT LAKES TONIGHT
...AS HIGH PRESSURE ANCHORED OVER THE ATLANTIC HINDERS PROGRESSION
OF A PLAINS FRONTAL SYSTEM INTO THE GREAT LAKES. CURRENT MODEL DATA
SUGGESTS THE WEAK BOUNDARY OVR WISCONSIN (ASSOCIATED WITH A SYSTEM
ORGANIZING OVER THE DESERT SOUTHWEST) WILL EVENTUALLY PUSH INTO THE
WESTERN GREAT LAKES AND LAKE MICHIGAN AFTER 06Z TONIGHT AS HIGH
PRESSURE PUSHES FURTHER INTO THE ATLANTIC. AT UPPER LEVELS...BROAD
500MB RIDGE ACRS THE ERN ONE THIRD OF THE COUNTRY WILL SLOWLY PUSH
EAST DURING THE NEXT 24HOURS...ALLOWING A DEEPENING 500MB TROUGH
OVER THE PLAINS TO PUSH INTO THE STATE SATURDAY AFTERNOON. AS A
RESULT THERMO PROFILES ACROSS THE GREAT LAKES WILL REMAIN NEARLY
UNCHANGED THROUGH TONIGHT...WITH 850MB TEMPS RANGING FROM AROUND -2C
NEAR SAGINAW BAY TO AROUND -6C ACROSS ERN UPPER MICHIGAN.

MODEL SOUNDINGS AND MSTR PROGS SHOW EXTREMELY DRY MID AND UPPER LVLS
(UNDER 50 PCT 850/500MB RH) LINGERING OVER NORTHERN MICHIGAN THROUGH
THIS EVENING...WHILE A SATURATED LAYER EXISTS FROM THE SFC THROUGH
925MB. HOWEVER MODEL SOUNDINGS SHOW 850/500MB RH INCREASING TO
GREATER THAN 80 PCT BETWEEN 06Z AND 12Z IN ADVANCE OF APPROACHING
PLAINS FRONTAL BOUNDARY. MODEL SOUNDING VERTICAL TEMPERATURE DATA
SHOWS THE COLDEST TEMP PROFILES ACROSS THE STRAITS AND ERN UPPER
MICHIGAN WHILE WARMER PROFILES LINGER OVER NRN LOWER. MODEL
SOUNDINGS SHOW AREAS NORTH OF GAYLORD WITH FREEZING LVLS UNDER 600FT
AT 09Z AS MID LVL MSTR INCREASES...WHILE AREAS SOUTH OF GAYLORD SHOW
FREEZING LVLS NEARING 2K FT WHILE MID LVLS MOISTEN.

OVERALL BASED OFF THE LATEST MODEL SOUNDING DATA...WILL CONTINUE
WITH CURRENT FORECAST TREND OF ANY PCPN THROUGH 06Z IN THE FORM OF
DRIZZLE ACRS THE CWA. AFTER 06Z...AS MSTR AND DYNAMICS INCREASE OVER
THE WRN LAKES WILL MENTION SNOW FOR ERN UPPER...RAIN AND SNOW FOR
THE TIP OF THE MITT...WITH ALL RAIN ACROSS THE SRN CWA. PCPN AMOUNTS
WILL BE LIGHT THROUGH THE OVERNIGHT HOURS WITH MODEL SOUNDINGS
SHOWING LIMITED MSTR WITH PWAT ARND 0.50IN. EXPECT CURRENT MILD
TEMPS IN THE LOWER 30S TO CONTINUE OVERNIGHT...A RESULT OF WARM MILD
LEVEL TEMP PROFILE LINGERING OVER THE GREAT LAKES.

&&

.SHORT TERM...(SATURDAY THROUGH MONDAY)
ISSUED AT 347 PM EST FRI DEC 26 2014

HIGH IMPACT WEATHER POTENTIAL: MINIMAL

FORECAST CHALLENGES: TIMING THE COLDER AIR BACK INTO THE REGION, AND
ANY SNOW ACCUMULATIONS WITH IT.

OVERVIEW(ANALYSIS AND FORECAST)...FLATTENING 500 MB RIDGE IS OVER
THE UPPER GREAT LAKES AS TWO TROUGH ARE STAGED TO THE WEST IN THE
GREAT PLAINS AND THE CANADIAN PRAIRIES. THE MAIN LOW IN THE GREAT
PLAINS/CENTRAL ROCKIES HAS HELPED TO SPLIT THE FLOW IN THE WEST ONLY
FOR THE NORTHERN AND SOUTHERN STREAMS TO MERGE ROUGHLY OVER THE
UPPER GREAT LAKES. DOWNSTREAM OF THE PLAINS 500 MB LOW IS THE SFC
TROUGH THAT IS DEVELOPING IN THE SOUTHERN PLAINS THAT WILL MOVE OVER
THE EASTERN GREAT LAKES SATURDAY/SUNDAY. THE WARM AIR THAT IS
EXPECTED TO GET WRAPPED INTO THE SYSTEM LOOKS TO PROBABLY PRODUCE
RAIN IN N LOWER AND LIGHT SNOW IN E UPPER.

(12/27)SATURDAY...AS THE SFC LOW MOVES INTO CENTRAL LAKE MICHIGAN BY
12Z, THE WARM AIR WILL HAVE WRAPPED INTO N LOWER TO AS FAR NORTH AS
THE STRAITS ON THE GFS WHILE THE ECMWF AND THE NAM SUGGEST A MIX, SO
KEPT THE MIX INLAND AND NORTH OF M-55 ON THE WEST SIDE, DRIZZLE
STILL LOOKS GOOD WITH THE LIMITED MOISTURE IN THE LOWER LEVELS OF
THE SOUNDING ON THE EAST SIDE OF THE STATE, AND LIGHT SNOW IN E
UPPER. THE ECMWF IS ABOUT 50 MILES SOUTH OF THE GFS TRACK, BUT THE
850 MB FREEZING LINE ARE MUCH CLOSER, SO WILL CONTINUE WITH THE MIX
IN THE INTERIOR HIGHLANDS, WITH THE RAIN OVER MOST OF N LOWER BY
18Z. BY 00Z, THE SFC LOW IS WELL INTO ONTARIO, SO COLD AIR BEGINS TO
POUR INTO THE FORECAST AREA, AND WE SHOULD SEE SOME CHANGE OVER LATE
IN THE AFTERNOON, MAINLY IN NW LOWER, AND PROBABLY A MIX IN NE
LOWER.

SATURDAY NIGHT...WATCHING THE SOUNDINGS, ANY RAIN WILL CONTINUE TO
CHANGE OVER TO SNOW SO THAT BY MIDNIGHT, WE SHOULD BE ALL SNOW.
HOWEVER, THE 700-500 MB LAYER RH DRIES OUT QUICKLY TO <30% AND THE
850 MB MOISTURE IS ONLY IN THE 50% RANGE. THE 850 MB TEMPERATURES BY
12Z HAVE FALLEN, BUT ONLY TO ABOUT -10C IN N LOWER, SO WILL KEEP THE
CHANCE OF SNOW OVER THE REGION AS THE LAKE EFFECT SNOW MACHINE IS
BARELY ABLE TO GET GOING.

(12/28)SUNDAY...CONDITIONS GET BETTER FOR LES SUNDAY MORNING AS THE
850-700 MB LAYER RH IS OVER 50% WITH THE 850 MB TEMPERATURES -12C IN
N LOWER AND -14C IN E UPPER. THE ECMWF LOOKS LIKE A COMPROMISE OF
THE NAM AND THE GFS. THE GFS IS FASTER AND DRYING OUT MUCH MORE THAN
THE OTHER TWO MODELS. SO HAVE KEPT AMOUNTS MINOR, EVENING IN E UPPER
AS THE MOISTURE IN THE 850-700 MB LAYER FALLS OFF BELOW 60%, BUT
WILL BE ENOUGH TO SUPPORT SOME SNOW. OVERNIGHT, THE CHANCE OF SNOW
WILL CONTINUE WITH THE NNW FLOW, AND COLD 850 MB TEMPERATURES. THE
MOISTURE DOES LOOK LIKE IT`S TRYING TO MOVE SOUTH. HOWEVER, THERE IS
SOME VERY DRY AIR ON THE NAM AND GFS THAT COULD PROHIBIT THE SNOW IN
E UPPER AND THE TIP OF THE MIT.

(12/29)MONDAY...STILL COLD ENOUGH FOR LES, BUT WITH SUCH DRY AIR IN
THE MIX ON THE GFS AND ECMWF IT MAY BE FLURRIES. HOWEVER, THE NAM IS
BEGINNING TO MOISTEN AGAIN SO THERE COULD BE SOME LIGHT SNOW NEAR
TVC IF THIS FLOW CONTINUES.

&&

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 347 PM EST FRI DEC 26 2014

COLD AIR WILL ONCE AGAIN FILTER INTO THE REGION ON THE BACKSIDE OF A
DEPARTING LOW. THE INFLUX OF COLD AIR WILL RESULT IN LINGERING
CHANCES FOR LAKE EFFECT SNOWS IN AREAS FAVORED WITH WEST AND
NORTHWEST FLOW. THIS WILL PERSIST THROUGH MOST OF THE WEEK...WITH A
COUPLE QUICK MOVING SHORTWAVE DISTURBANCES ARRIVING THURSDAY AND
FRIDAY. THE INITIAL SHORTWAVE WILL BRING SOME CHANCES FOR SNOW TO
MUCH OF THE FORECAST AREA...WHILE THE FRIDAY SYSTEM LOOKS TO AFFECT
MAINLY THE TIP OF THE MITT AND EASTERN U.P. PORTIONS OF THE CWA.
LACK OF AVAILABLE MOISTURE SHOULD KEEP ANY TOTALS MODEST. HIGH
TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL IN THE LOW TO MID
20S...WITH SOME AREAS IN THE TEENS MID WEEK. LOW TEMPERATURES WILL
BE IN THE TEENS...WITH SOME INTERIOR LOCATIONS DIPPING INTO SINGLE
DIGITS MID WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 645 PM EST FRI DEC 26 2014

MVFR TO IFR. SOME -RA/-DZ LATE TONIGHT/SATURDAY. LLWS SAT
AFTERNOON.

DEVELOPING LOW PRESSURE IN FAR WESTERN MISSOURI WILL MOVE
NE...CROSSING NORTHERN MI SAT AFTERNOON. MOISTURE WILL DEEPEN
AHEAD OF THE SYSTEM...ALLOWING PRECIP TO DEVELOP LATE TONIGHT INTO
SATURDAY. FOR THE TAF SITES...THIS PRECIP SHOULD BE ALMOST ALL
RAIN. AS WARMER/MORE MOIST AIR MOVES IN...CIGS AND VSBYS WILL
DETERIORATE. PRESENT MVFR CIGS/VFR VSBYS WILL DEVOLVE TO IFR
CIGS/VSBYS BY SATURDAY MORNING...AND REMAIN THERE UNTIL VERY LATE
SATURDAY WHEN A COLD FRONT MOVES IN.

LIGHT SURFACE WINDS TONIGHT/SATURDAY...W TO NW WINDS DEVELOPING
VERY LATE SATURDAY MBL/TVC/PLN. LLWS SAT AFTERNOON WITH STRONG SW
WINDS JUST OFF THE DECK.


&&

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

$$

UPDATE...JAZ
NEAR TERM...SWR
SHORT TERM...JSL
LONG TERM...ALM
AVIATION...JAZ



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