Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 190513
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
113 AM EDT SUN APR 19 2015

.UPDATE...
ISSUED AT 911 PM EDT SAT APR 18 2015

CIRRUS WILL BE ON AN INCREASING TREND OVERNIGHT (TO SOME
DEGREE)...BUT MOSTLY CLEAR STILL LOOKS TO HOLD UNTIL ALMOST
DAYBREAK. OTHERWISE...THE BIG BLUE /H/ TO OUR NE WILL MAINTAIN
VERY QUIET WX...AND NO MAJOR CHANGES ARE NEEDED.

&&

.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 327 PM EDT SAT APR 18 2015

...SOME HIGH CLOUDS TONIGHT...

HIGH IMPACT WEATHER POTENTIAL: MINIMAL.

PATTERN SYNOPSIS/FORECAST: EARLY AFTERNOON SURFACE ANALYSIS SHOWS
HIGH PRESSURE CENTERED OVER NORTHWEST ONTARIO BUILDING SOUTHEAST
ACROSS THE GREAT LAKES REGION (3-4MB/3H PRESSURE RISES ACROSS
NORTHEAST ONTARIO/LAKE HURON).  A COLD FRONT THAT MOVED THROUGH
NORTHERN MICHIGAN DURING THE EARLY MORNING HOURS NOW JUST SOUTH OF
THE STATE LINE.  CONFLUENT FLOW ALOFT ACROSS MICHIGAN BETWEEN
NORTHWESTERLY NORTHERN BRANCH FLOW TO THE NORTH AND ANTICYCLONIC
FLOW EMANATING TO THE EAST OF A BROAD SOUTHERN BRANCH UPPER LOW
SPINNING OVER THE CENTRAL HIGH PLAINS AND ROCKIES.  NICE POCKET OF
DRY AIR HAS SETTLED ACROSS UPPER/NORTHERN LOWER MICHIGAN THIS
AFTERNOON...AND WITH MIXING DEW POINTS HAVE DROPPED OFF AS A RESULT.

SURFACE HIGH FORECAST TO MOVE INTO QUEBEC OVERNIGHT...WITH A TIGHTER
PRESSURE GRADIENT AND STRONGER EAST/SOUTHEAST BOUNDARY LAYER FLOW
DEVELOPING.  RIDGING ALOFT WILL CROSS THE STATE OVERNIGHT AS WELL.

PRIMARY FORECAST CONCERNS: MINIMAL.

TONIGHT...ANOTHER QUIET NIGHT EXPECTED WITH JUST SOME HIGH CLOUDS
ADVANCING FROM THE SOUTHWEST AS UPPER LEVEL RIDGE AXIS CROSSES THE
STATE.  WINDS SHOULD DROP OFF INITIALLY THIS EVENING BUT AS PRESSURE
GRADIENT TIGHTENS UP OVERNIGHT WINDS WILL SWING AROUND TO THE
EAST/SOUTHEAST AND PICK UP ONCE AGAIN.  GIVEN DRY AIR MASS IN PLACE
AND INITIALLY LIGHT WINDS EXPECT TEMPERATURES TO SLIP INTO THE 30S
TONIGHT MOST AREAS...SOME 20S ACROSS NORTHWEST CHIPPEWA COUNTY WHERE
AFTERNOON TEMPERATURES ARE STUCK IN THE UPPER 30S/40S THANKS TO
WINDS OFF THE LINGERING LAKE SUPERIOR GLACIER.

&&

.SHORT TERM...(SUNDAY THROUGH TUESDAY)
ISSUED AT 327 PM EDT SAT APR 18 2015

HIGH IMPACT WEATHER: MINIMAL

FORECAST CHALLENGE: TIMING OF THE RAIN SUNDAY INTO SUNDAY NIGHT.

(04/19)SUNDAY...LOOKING AT THE GFS THE LAST FEW DAYS, HAS BEEN ONE
OF A BACK AND FORTH ON WHETHER THE RAIN WILL GET INTO E UPPER. ONE
OR TWO 6 HOUR RUNS SAYS YES, THEN ON THE 12Z RUN NO. SUCH IS THE
CASE, AGAIN ALTHOUGH IT DIDN`T BACK OFF THE RAIN ENTIRELY. LOOKING
AT THE 850 MB MOISTURE, WHILE THE GFS HAS BEEN FAIRLY WELL IN LINE
WITH THE ECMWF, THE QPF ON THE GFS HAS OUT RUN THE ECMWF. SEEING
THAT THE LOW LEVEL MOISTURE HAS BEEN LACKING DUE TO THE SFC HIGH
(TODAY A HUDSON BAY HIGH) MOVING IN AND AROUND THE REGION THIS WEEK.
SO HEDGED CLOSER TO THE SREF MEAN IDEA, WHICH SEEMS A DECENT
COMPROMISE BETWEEN THE TWO, AND FOR WHAT IT`S WORTH, THE NAM IS
ABOUT AS SLOW AS THE ECMWF. SO THE RAIN WILL ARRIVE IN N LOWER
PROBABLY AFTER 21Z AND IN E UPPER AFTER 00Z.

AFTER 00Z, THE IDEA IS PRETTY SIMPLE, THE SFC LOW ROTATES UP OVER
MICHIGAN THROUGH THE NIGHT WITH A COUPLE OF 500 MB SHORTWAVE TROUGHS
MOVING THROUGH THE REGION AT THE SAME TIME. WITH THE PWAT OF 0.75"
TO 1.0" AND THE FORCING WITH THE SYSTEM WILL EXPECT THAT THERE WILL
BE PERIODS OF RAIN THROUGH THE NIGHT.

(4/19)MONDAY...THE RAIN SHOULD CONTINUE INTO THE DAY AS THE 500 MB
LOW MOVING OUT OF MANITOBA AND INTO THE UPPER GREAT LAKES, HOWEVER,
IT WILL PROBABLY BECOME MORE SHOWERY AS DRY AIR ENTRAINED ALOFT GETS
PULLED INTO THE REGION AHEAD OF THE LOW. SO HAVE CHANCE TO LIKELY
POPS AS THE MOISTURE VARIES WITH TIME THROUGH THE DAY.

AROUND 00Z AND THERE AFTER, IT LOOKS LIKE THE 850 MB TEMPERATURES
FALL ENOUGH THAT THERE WILL BE A RAIN/SNOW MIX THAT WILL LAST
THROUGH THE NIGHT. ALTHOUGH, IT COULD BE ALL SNOW BY DAY BREAK,
ALBEIT MINOR TO LIGHT ACCUMULATIONS, AS THE 850 MB TEMPERATURES FALL
TO AROUND -7C BY 12Z OVER N LAKE MICHIGAN.

(4/20)TUESDAY...THE 500 MB LOW CONTINUES TO SPIN OVER THE UPPER GREAT
LAKES. THIS CONTRIBUTES TO THE GFS BEING ABOUT 2C COOLER THAN THE
ECMWF(00Z), SO WILL HAVE A MIX THROUGH THE DAY AS THE SFC
TEMPERATURES RISE TO THE UPPER 30S TO LOWER 40S, EVEN IN E UPPER.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 327 PM EDT SAT APR 18 2015

A STUBBORN...SLOW MOVING...500MB CUTOFF LOW OVER THE GREAT LAKES AND
ONTARIO WILL LEAD TO BELOW NORMAL TEMPS AND SOME PRECIPITATION INTO
FRIDAY. THIS CUTOFF LOOKS TO STAY AROUND THROUGH MOST OF THE WEEKEND
BEFORE FINALLY LIFTING INTO NEW ENGLAND. WITH SOME WEAKER SHORTWAVE
ENERGY PASSING OVERHEAD AROUND THE MAIN LOW...CHANCES FOR SHOWERS
WILL REMAIN THROUGH MOST OF THE PERIOD. AND...AS PREVIOUSLY
MENTIONED...COOL OVERNIGHT TEMPS COULD SEE SOME SNOW MIXING IN.

THINGS WILL BEGIN TO CLEAR UP THROUGH THE WEEKEND AS THE CUTOFF LOW
LIFTS...BUT AN OMEGA BLOCK LOOKS TO BE SETTING UP BY SATURDAY NIGHT
WITH ANOTHER CLOSED LOW IN THE GULF OF ALASKA/NORTHERN PACIFIC AND
BROAD HIGH PRESSURE OVER THE CONUS. SITUATED SQUARELY IN THE
DESCENDING/CAA SIDE OF THIS...WE COULD BE IN FOR A STRETCH OF DRY
WEATHER AND BELOW NORMAL TEMPS UNTIL THE BLOCK BREAKS DOWN. ECMWF IS
A BIT STRONGER WITH THIS...BUT OTHER GUIDANCE PICKING IT UP AS
WELL.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 113 AM EDT SUN APR 19 2015

SCT/BKN HIGH CLOUDS WILL INCREASE...LOWER AND THICKEN TONIGHT AND
SUNDAY AS LOW PRESSURE AND ASSOCIATED DEEP MOISTURE LIFT NORTHWARD
INTO INTO LWR MICHIGAN. WIDESPREAD PRECIP WILL DEVELOP LATE SUNDAY
AFTERNOON AND WILL CONTINUE ACROSS OUR ENTIRE AREA THRU SUNDAY
NIGHT AS THE SURFACE LOW CENTER LIFTS N/NE THRU THE THUMB AREA.
LLWS WILL DEVELOP OVERNIGHT AHEAD OF THIS SYSTEM...WHICH WINDS AT
THE SURFACE REMAIN E/NE UNDER 10 KTS. SURFACE WIND WILL STRENGTHEN
TO 15 TO 25 KTS ON SUNDAY ONCE DAYTIME MIXING BEGINS.

&&

.MARINE...
ISSUED AT 327 PM EDT SAT APR 18 2015

TONIGHT: PRESSURE GRADIENT BUILDS TONIGHT AS HIGH PRESSURE BUILDS
INTO QUEBEC AND PRESSURES FALL ACROSS THE PLAINS.  EAST/SOUTHEAST
WIND WILL INCREASE OVERNIGHT.

OUTLOOK: SMALL CRAFT ADVISORIES LIKELY FOR SUNDAY/SUNDAY NIGHT MOST
NEARSHORE ZONES.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 9 AM EDT MONDAY
     FOR LHZ345>347.

LM...NONE.
LS...NONE.
&&

$$

UPDATE...JAZ
NEAR TERM...JPB
SHORT TERM...JSL
LONG TERM...ALM
AVIATION...MLR
MARINE...JPB


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