Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 031948
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
348 PM EDT MON AUG 3 2015

.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 345 PM EDT MON AUG 3 2015

HIGH IMPACT WEATHER: NONE

SHORTWAVE OVER SOUTHERN ONTARIO AND COLD FRONT DRAPED ACROSS
NORTHERN MICHIGAN THIS AFTERNOON HELPING TO DRIVE SOME SHOWER AND
THUNDERSTORM DEVELOPMENT. CAPE VALUES STARTED OUT AROUND 500J/KG AT
12Z BUT WILL DECREASE DURING THE DAY WITH COOLER DRIER AIR MOVING
IN. PRETTY SCATTERED AT THIS TIME AND DIURNALLY DRIVEN AND EXPECT
COVERAGE TO DECREASE WITH THE LOSS OF DAYTIME HEATING LATER THIS
EVENING. OTHERWISE...MASS OF CLOUDS IN UPPER COLD POOL WILL MOVE IN
TONIGHT. 850MB TEMPS DROP INTO THE SINGLE DIGITS OVERNIGHT...SO
COULD BE A LAKE EFFECT COMPONENT TO SHOWERS TOWARD MORNING.

&&

.SHORT TERM...(TUESDAY THROUGH THURSDAY)
ISSUED AT 345 PM EDT MON AUG 3 2015

PRIMARY FORECAST CHALLENGE: WATERSPOUTS ON TUESDAY.

(8/4)TUESDAY...MODELS PEG ANOTHER SFC TROUGH TO MOVE THROUGH THE
FORECAST AREA IN THE MORNING, TO BE CLEARING THE FORECAST AREA BY
00Z. THE COOLEST AIR LOOKS TO MOVE INTO THE FORECAST AREA (BASED ON
THE 850 MB TEMPERATURES) DURING THE AFTERNOON. THE 850 MB
TEMPERATURES FALL TO +5C ON THE GFS AND +7C ON THE ECMWF. THE WATER
TEMPERATURES IN N LAKE MICHIGAN ARE +20C, SO WE HAVE ENOUGH FOR LAKE
ENHANCED/EFFECT SHOWERS OVER THE NORTHERN PART OF LAKE MICHIGAN AND
NW LOWER. KEPT THE POPS IN THE CHANCE CATEGORY FOR THE AFTERNOON AS
THE SHOWERS ARE EXPECTED TO BE VERY LIGHT AND SCATTERED.

NOW FOR THE WATERSPOUTS...AM HIGHLY UNDERWHELMED BY THE 850 MB
TEMPERATURES. WE ARE JUST GETTING INTO THE NOMOGRAM WITH THE DELTA
TS AT THE MOST (THIS IS ON THE GFS) 15C WHICH THE LOWER BOUND, FOR
SOMETHING UNDER AN UPPER LOW SCENARIO. THE ECMWF AND NAM HAVE ABOUT
13C. SO AM NOT EXPECTING ANYTHING. IT WOULD PROBABLY BE A 1 OR 2 ON
THE SWI BY SZILAGYI. SO IT`S NOT OUT OF THE REALM OF POSSIBILITIES,
BUT AM NOT EXPECTING ANY REPORTS.

(8/5)WEDNESDAY...HEIGHTS BUILD AT 500 MB AND THE 850 MB TEMPERATURES
WARM TO AROUND 8C BY THE AFTERNOON, AND WITH THE SFC HIGH BUILDING
INTO THE REGION, IT LOOKS LIKE IT MAY BE PARTLY SUNNY AND DRY. THIS
WILL CONTINUE INTO THE NIGHT AS WELL, SORT OF. THE ECMWF AND THE GFS
ARE AT ODDS AS TO WHETHER A SFC LOW MAKES IT INTO THE FORECAST AREA.
THE ECMWF HAS IT IN THE BOUNDARY WATERS AT 12Z, WHILE THE GFS HAS IT
MOVING OUT OF THE IOWA WITH RAIN GETTING INTO THE SW COUNTIES. WILL
LEAVE THE NIGHT DRY FOR NOW.

(8/6)THURSDAY...THE GFS CONTINUES TO PUSH THE LOW ALONG THE
MICHIGAN/INDIANA BOARDER WITH THE RAIN AFFECTING AREAS SOUTH OF M-
32. THE ECMWF HAS LIGHT RAIN IN UPPER MICHIGAN AS THE SFC LOW MOVES
TO W UPPER. HAVE SOME SLIGHT CHANCE POPS FOR THE RAIN ALONG THE
SOUTHERN BORDER. WILL SEE HOW THIS WORKS.

&&

.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 345 PM EDT MON AUG 3 2015

CHANCE POPS CONTINUE THROUGH THE WEEKEND WITH CONTINUED UNCERTAINTY
ON THE EVOLUTION OF H5 RIDGING AND WEAK SHORTWAVES MOVING THROUGH.
THE EASTERN EXTENT OF THE RIDGE WILL INFLUENCE WHERE THE SHORTWAVE
MOVES...AS WELL AS OUR PRECIP CHANCES. SHOULD BE ABLE TO GET A
BETTER HANDLE ON THE PATTERN EVOLUTION IN THE COMING DAYS.
TEMPERATURES WILL BE BELOW NORMAL TO START THE PERIOD...WARMING BACK
TO NORMAL BY THE WEEKEND.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1248 PM EDT MON AUG 3 2015

LOW TO MID LEVEL DECK UNDER UPPER COLD POOL EXPECTED TO MOVE IN
TONIGHT. CEILINGS WILL MOSTLY REMAIN VFR BUT COULD BE SOME MVFR
AFTER SUNRISE TOMORROW. FEW SHOWERS AROUND THIS AFTERNOON ESPECIALLY
SOUTH OF AN MBL-APN LINE BUT MOSTLY SCATTERED. GENERAL NW FLOW AT
THE SURFACE.


&&

.MARINE...
ISSUED AT 345 PM EDT MON AUG 3 2015

OTHER THAN A FEW GUSTS TO 20 KTS...NOT MUCH GOING ON
OVERNIGHT. A FEW SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE.
COLD AIR ALOFT MOVING IN AND WARM LAKES...GETTING CLOSE TO LAKE-AIR
DELTA THRESHOLDS FOR WATERSPOUT POSSIBILITIES...BUT PROBABLY NOT
COLD ENOUGH ALOFT. COLDEST AIR GOES OVERHEAD TOMORROW AFTERNOON.

&&

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

$$

NEAR TERM...KJF
SHORT TERM...JSL
LONG TERM...ALM
AVIATION...KJF
MARINE...KJF



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