Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 311045
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
645 AM EDT FRI JUL 31 2015

.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 444 AM EDT FRI JUL 31 2015

...FEW SHOWERS POSSIBLE IN SPOTS TODAY/TONIGHT...

HIGH IMPACT WEATHER POTENTIAL: ELEVATED FIRE DANGER THIS AFTERNOON.

PATTERN SYNOPSIS/FORECAST: FAIRLY TIGHT PRESSURE GRADIENT REMAINS
ACROSS THE GREAT LAKES EARLY THIS MORNING...SURFACE TROUGH LIES
ACROSS NORTHWEST ONTARIO/NORTHERN MINNESOTA.  SEVERAL SHORT WAVE
TROUGHS WITHIN NORTHWEST FLOW ALOFT PER WATER VAPOR IMAGERY...ONE
LOCATED EAST OF GEORGIAN BAY WITH AN ASSOCIATED POTENTIAL VORTICITY
AXIS THAT EXTENDS BACK ACROSS LOWER MICHIGAN/WESTERN UPPER MICHIGAN/
NORTHWEST ONTARIO.  WITHIN THIS AXIS IS ANOTHER VORTICITY CENTER
CROSSING EASTERN UPPER MICHIGAN...AND A BETTER DEFINED SHORT WAVE
TROUGH MOVING INTO FAR NORTHWEST MINNESOTA.  THESE VARIOUS WAVES
RESULTING IN A BROKEN AREA OF (DIMINISHING) SHOWERS TRACKING
SOUTHEAST FROM NORTHWEST ONTARIO AND ACROSS LAKE SUPERIOR TOWARD THE
UPPER PENINSULA.  NOT MUCH CLOUD COVER ACROSS THE FORECAST AREA
EARLY THIS MORNING...BETTER CLOUD/SHOWER COVERAGE CLOSER TO THE
MINNESOTA SHORT WAVE TROUGH OVER NORTHEAST MINNESOTA/NORTHWEST
ONTARIO.

SHORT WAVE TROUGH MOVING THROUGH MINNESOTA EARLY THIS MORNING WILL
CROSS MICHIGAN DURING THE DAY TODAY BEFORE TRACKING INTO THE LOWER
GREAT LAKES TONIGHT.  THIS WILL BE FOLLOWED BY ANOTHER QUICK MOVING
SHORT WAVE/MID LEVEL JET STREAK OVERNIGHT.  WEST-NORTHWEST BOUNDARY
LAYER FLOW WILL PERSIST BETWEEN LOW PRESSURE OVER HUDSON BAY AND A
NARROW HIGH PRESSURE RIDGE OVER THE MIDWEST.

PRIMARY FORECAST CONCERNS: IMPACTS OF PASSING SHORT WAVE TROUGHS.
ELEVATED FIRE DANGER.

TODAY...WATER VAPOR IMAGERY TRENDS SUGGEST UPWARD MOTION FIELD
ASSOCIATED WITH APPROACHING SHORT WAVE TROUGH WILL BE SPREADING INTO
NORTHERN PORTIONS OF THE FORECAST AREA SHORTLY AFTER DAYBREAK...BUT
INITIALLY LOOKS LIKE THINGS MAY BE QUIET TO START THE DAY WITH SOME
MID CLOUDS HEADED TOWARD EASTERN UPPER.  SUSPECT LIKE YESTERDAY...
QUESTION FOR TODAY IS WHETHER ENOUGH DESTABILIZATION WILL TAKE PLACE
TO ALLOW FOR NEW CONVECTIVE DEVELOPMENT.  THINK THE IDEA OF SOME
DEVELOPMENT ACROSS THE NORTHERN THIRD OR SO OF THE FORECAST AREA IS
NOT UNREASONABLE...AT LEAST FROM A PROBABILISTIC STANDPOINT...
CLOSER TO THE TRACK OF THE PASSING SHORT WAVE TROUGH AND WHERE LOW
LEVEL MOISTURE LIKELY TO REMAIN A LITTLE HIGHER.  NOT CONVINCED YET
THAT THIS IS GOING TO BE A HUGE DEAL BUT THERE IS PROBABLY ENOUGH
POTENTIAL THERE TO JUSTIFY SOME MEASURABLE POPS.  WINDS WILL BE A
LITTLE GUSTY AGAIN WITH DEEP MIXING BUT NOT TO THE EXTENT OF
THURSDAY`S GUSTS (MORE IN THE 20-25MPH RANGE THIS AFTERNOON).  DEEP
MIXING SHOULD ALSO PUSH TEMPERATURES BACK INTO THE 80S ACROSS MUCH
OF NORTHERN LOWER THIS AFTERNOON.  LIKE THURSDAY...THE COMBINATION
OF WARM TEMPERATURES/GUSTY WINDS/RECENT DRYNESS WILL LEAD TO
ELEVATED FIRE DANGER ONCE AGAIN THIS AFTERNOON.

TONIGHT...SECONDARY SHORT WAVE TROUGH/JET STREAK FORECAST TO ARRIVE
LATER TONIGHT...CAN ENVISION THIS FEATURE DRAGGING IN AN AREA OF
SHOWERS ALONG WITH IT...AND THE POSSIBILITY THAT SOME NOCTURNAL
INSTABILITY OVER THE WARMING LAKES MICHIGAN/HURON (GETTING TO THAT
TIME OF YEAR) WILL CONTRIBUTE AS WELL IN GENERATING SHOWERS AND
PERHAPS A THUNDERSTORM.

&&

.SHORT TERM...(SATURDAY THROUGH SUNDAY NIGHT)
ISSUED AT 444 AM EDT FRI JUL 31 2015

PRIMARY FORECAST CHALLENGE: PERIODS OF LIGHT SHOWER POTENTIAL
THROUGH THE WEEKEND.

FORECAST DETAILS...USUALLY I BREAK THIS INTO THE SPECIFIC DAYS, BUT
FOR THE MOST PART, THE IDEA FOR SATURDAY AND SUNDAY ARE BASICALLY
THE SAME. AS THE HUDSON BAY 500 MB LOW SITS, WITH VARIOUS SPOKES OF
MOISTURE/ENERGY ROTATING AROUND THE LOW PRODUCING DIURNAL
CLOUDINESS, AND AT TIME DIURNAL SHOWERS. AS WAS SEEN YESTERDAY
(THURSDAY) THE SHOWERS FIRED UP IN THE DIURNAL CLOUDS, ONLY TO FADE
AWAY OVERNIGHT. BASED ON THE CURRENT MODEL OUTPUT, SATURDAY LOOKS
LESS SHOWERY THAN SUNDAY AS THE INITIAL IMPULSE (ON SATURDAY) TO
ROTATES INTO THE UPPER GREAT LAKES HAS LITTLE TO NO INSTABILITY WITH
THE ML AND SFC CAPES <100 J/KG. SO WILL EXPECT A DAY SIMILAR TO
THURSDAY AS THE CLOUD STREETS GENERATE DOWN LAKE WITH A FEW
CONGEALING INTO SOME MINOR SHOWERS.

FOR SUNDAY, A WEAK SFC TROUGH LOOKS TO BE SUPPORTING THE 500 MB
SHORTWAVE TROUGH, WHICH BEGINS TO PUSH THE WARM AIR NORTHEAST INTO
THE FORECAST AREA. MODEL ML CAPES LOOK TO BE AROUND 600 J/KG WITH A
MLCINH OF 40 J/KG. SO IF THE WARM FRONT CAN KICK SOMETHING OFF THERE
COULD BE THUNDER, BUT BASED ON THESE PROFILES WILL EXPECT A LITTLE
MORE ORGANIZED SHOWER ACTIVITY. CAN THERE BE THUNDER? SURE, BUT IT
WILL BE LESS LIKELY THAN THE RAIN SHOWERS.

&&

.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 444 AM EDT FRI JUL 31 2015

EXTENDED (MONDAY THROUGH THURSDAY)...IT`S BEGINNING TO LOOKS AS IF
THE TROUGH OVER HUDSON BAY MAY BREAKDOWN AFTER THURSDAY AS THE WHOLE
PATTERN WITH THE GULF OF ALASKA LOW BEGINNING TO BREAK INTO PIECES,
WITH ONE PIECE ENDING UP IN THE PAC NW. THIS LOOKS TO PUSH THE RIDGE
TO THE EAST, AND THE HUDSON BAY LOW BEGINS TO MOVE EAST INTO THE
CANADIAN MARITIMES. HOWEVER, FOR MONDAY THROUGH WEDNESDAY, THE
PATTERN IS A SLOW MOVING COOL, SOMEWHAT WET PATTERN. I SAY SOMEWHAT
WET, DUE TO THE FACT THAT IT LOOKS LIKE A MID FALL COOL RAIN SHOWER
PATTERN, WITH A LITTLE THROWN IN AT TIMES. THE CIPS ANALOGS SHOW
BELOW NORMAL TEMPERATURES THROUGH THE PERIOD, WITH THE THREE DAY
MEAN PRECIPITATION AMOUNTS OF 0.25". SO BASED ON THAT AND THE DRYNESS
OF THE ECMWF THROUGH MOST OF THE PERIOD, WE BARELY GET TO 30% CHANCE
FOR MEASURABLE RAIN ON ANY DAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 644 AM EDT FRI JUL 31 2015

MOSTLY PREVAILING VFR CONDITIONS TODAY...SOME GUSTY WINDS THROUGH
THE AFTERNOON HOURS ALONG WITH SCATTERED SHOWERS AROUND PLN/APN.

&&

.MARINE...
ISSUED AT 444 AM EDT FRI JUL 31 2015

TODAY/TONIGHT...MARGINAL FOR SMALL CRAFT CONDITIONS TODAY...WITH
HIGHER WIND GUSTS POSSIBLE FOR NEARSHORE ZONES IMPACTED BY AN
OFFSHORE WIND COMPONENT IN WEST-NORTHWEST WINDS.

OUTLOOK...LIGHTER WINDS ON TAP FOR SATURDAY WITH ADDITIONAL HAZARDS
NOT EXPECTED THROUGH SATURDAY NIGHT.


&&

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

$$

NEAR TERM...JPB
SHORT TERM...JSL
LONG TERM...JSL
MARINE...JPB


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