Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 261949
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
349 PM EDT TUE AUG 26 2014

.SYNOPSIS...
ISSUED AT 344 PM EDT TUE AUG 26 2014

COOLER AND LESS HUMID AIR WILL GRADUALLY REPLACE THE WARM AND HUMID
AIR FROM THE LAST SEVERAL DAYS AS HIGH PRESSURE SETTLES IN THROUGH
THURSDAY. THE NEXT POSSIBLE CHANCE FOR SHOWERS AND STORMS WILL BE
THURSDAY NIGHT THROUGH THE UPCOMING WEEKEND.

&&

.SHORT TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 344 PM EDT TUE AUG 26 2014

...MUCH COOLER TONIGHT...

HIGH IMPACT WEATHER POTENTIAL: NONE.

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: MUCH FLATTER AND MORE
PROGRESSIVE FLOW PATTERN FOUND ACROSS THE NORTHERN LAKES THIS
AFTERNOON...WITH LEAD RIDGE KILLING SHORTWAVE RACING ACROSS JAMES
BAY...WHILE SECOND SHORTWAVE TROUGH BEGINS TO PUNCH INTO THE
NORTHERN PLAINS/SOUTH CENTRAL CANADA. WEAK SURFACE COLD FRONT
STEADILY PUSHING OFF TO THE EAST...EXITING INTO LAKE HURON. RATHER
AGGRESSIVE PUSH OF LOW LEVEL DRYING LAGGING BEHIND THIS FRONT BY
SEVERAL MILES...WITH LEADING EDGE OF MUCH DRIER AIR NOW PUSHING INTO
FAR NORTHWEST LOWER MICHIGAN. ALL THE ACTIVE WEATHER NOW DISPLACED
OFF TO OUR SOUTH WHERE MUCH DEEPER MOISTURE AND INSTABILITY RESIDE.
AS MENTIONED...PATTERN IS PROGRESSIVE ONE...WITH NEXT UPSTREAM WAVE
QUICKLY PUSHING INTO OUR AREA BY WEDNESDAY MORNING.

PRIMARY FORECAST CONCERNS/CHALLENGES: CLOUD AND TEMPERATURE TRENDS.
LATE NIGHT SPRINKLE POSSIBILITY WILL ALSO NEED TO BE ADDRESSED.

DETAILS: REALLY NOT TOO MUCH TO TALK ABOUT TONIGHT AS LOW LEVELS
CONTINUE TO DRY OUT WITH SURFACE HIGH PRESSURE CONTINUING TO BUILD
INTO THE NORTHERN LAKES. BAND OF DEEPER MID AND UPPER LEVEL MOISTURE
ARRIVES LATE NIGHT WITH APPROACHING SHORTWAVE AND UPPER LEVEL SPEED
MAX. THAT SAID...OVERALL FORCING REMAINS LIMITED...AND MODEL DERIVED
SOUNDING SUPPORT SIMPLE EXTRAPOLATION THAT SUB H8 LEVELS WILL REMAIN
DRY OVERNIGHT. WILL CONTINUE WITH A DRY FORECAST...ALTHOUGH SUPPOSE
A FEW SPRINKLES JUST MIGHT REACH THE SURFACE. WILL LEAVE THIS AS A
NOW CAST ISSUE GIVEN OVERALL LOW CONFIDENCE OF THIS OCCURRING.
SEVERAL DEGREES CHILLIER TONIGHT THAN THE PAST SEVERAL...WITH LOWS
BY MORNING MOSTLY IN THE UPPER 40S AND LOWER 50S.

&&

.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
ISSUED AT 344 PM EDT TUE AUG 26 2014

...GREAT COUPLE OF DAYS UPCOMING/TURNING WET FOR THE HOLIDAY
WEEKEND...

HIGH IMPACT WEATHER POTENTIAL: MINIMAL OUTSIDE OF VARYING
THUNDERSTORM CHANCES.  SOME POTENTIAL FOR HEAVIER RAINFALL THURSDAY
NIGHT INTO FRIDAY THOUGH A LOT OF UNCERTAINTY REGARDING THAT
EVOLUTION.

PATTERN SYNOPSIS/FORECAST: PROGRESSIVE FIVE WAVE HEMISPHERIC PATTERN
IN PLACE...AXIS OF MODEST WESTERLIES STRETCHING ACROSS THE NORTH
PACIFIC/SOUTHERN CANADA AND OUT INTO THE NORTH ATLANTIC.  WESTERN
LONG WAVE TROUGH IS ACTUALLY SPLIT WITH A LOW AMPLITUDE NORTHERN
BRANCH SHORT WAVE TROUGH CROSSING THE PRAIRIE PROVINCES...AND A MORE
PRONOUNCED SOUTHERN BRANCH TROUGH OVER THE GREAT BASIN.  BROAD UPPER
RIDE EXTENDS FROM THE DESERT SOUTHWEST/SOUTHERN PLAINS NORTHEAST TO
THE MID ATLANTIC/SOUTHEAST COAST.  UPPER GREAT LAKES BENEATH THE
SOUTHERLY FRINGES OF THE NORTHERN BRANCH WESTERLIES CROSSING
SOUTHERN CANADA.  SURFACE COLD FRONT RUNS FROM THE ONTARIO/QUEBEC
BORDER THROUGH LOWER MICHIGAN TO THE MID MISSISSIPPI VALLEY...THEN
TURNS WEST ACROSS THE CENTRAL PLAINS/CENTRAL ROCKIES.  1024MB
SURFACE HIGH CENTERED OVER THE DAKOTAS.  PLENTY OF MOISTURE AHEAD OF
THE FRONT WITH 60+F DEW POINTS UP INTO QUEBEC.  MUCH COOLER/DRIER
AIR BEHIND THE BOUNDARY WITH 850MB TEMPERATURES DROPPING BACK INTO
THE SINGLE DIGITS ACROSS NORTHERN MINNESOTA/NORTHWEST ONTARIO...
PRECIPITABLE WATER VALUES OFF 12Z SOUNDINGS DROP FROM 1.43 INCHES
AT DTX TO 0.65 AT INL.

LARGE SCALE FEATURES NOT EXPECTED TO SHIFT MUCH IN THE MEAN THROUGH
THE REMAINDER OF THE WEEK.  SOUTHERN PORTION OF WESTERN SPLIT FLOW
CUTS OFF AND DRIFT EAST INTO THE ROCKIES AS THE WEEK PROGRESSES...
WITH THE UPPER LAKES REMAINING ON THE SOUTHERN EDGE OF STRONGER
WESTERLIES TO THE NORTH.  NORTHERN BRANCH SHORT WAVE ENERGY SLIDES
BY FOR WEDNESDAY...WITH ANOTHER AREA OF HEIGHT FALLS LIKELY PASSING
NEAR OR JUST NORTH OF MICHIGAN IN THE SATURDAY TIME FRAME.  WESTERN
MEAN TROUGH EXPECTED TO BE REINFORCED DURING THE COMING HOLIDAY
WEEKEND...WHICH IN TURN MAY PUSH REMNANTS OF SOUTHERN BRANCH ENERGY
INTO OUR NECK OF THE WOODS TO ROUND OUT THE THREE DAY WEEKEND.
UPSTREAM HIGH PRESSURE WILL BUILD INTO THE UPPER LAKES FOR MIDWEEK...
AND SHOULD REMAIN IN CONTROL THROUGH THURSDAY...AFTER WHICH MOISTURE
WILL BEGIN TO RETURN TO THE UPPER LAKES.

PRIMARY FORECAST CONCERNS (NEAR TERM): IMPACTS WITH SHORT WAVE
PASSAGE FOR THE FIRST HALF OF WEDNESDAY...COOL TEMPERATURES THURSDAY
MORNING...THEN RAMPING UP THE THREAT FOR RAIN HEADING INTO FRIDAY.

NEAR TERM (WEDNESDAY/THURSDAY): QUICK MOVING SHORT WAVE TROUGH
CURRENTLY OVER SOUTHEAST SASKATCHEWAN...NOT MUCH MOISTURE WITH IT AT
THIS POINT BUT IT IS MOVING INTO AN AREA OF CLOUDS/SPOTTY SHOWERS
OVER THE DAKOTAS.  SO ANTICIPATE THAT THIS FEATURE WILL GRAB SOME OF
THIS MOISTURE AND DRAG IT ACROSS  NORTHERN MICHIGAN WEDNESDAY
MORNING.  SO DAY WILL START OUT ON THE CLOUDY SIDE...NOT SURE IF
THERE IS ENOUGH TO WARRANT A MENTION OF MEASURABLE PRECIPITATION BUT
SOME SPRINKLES ACROSS EASTERN UPPER AND FAR NORTHERN LOWER A
REASONABLE EXPECTATION AS LOW LAYERS EXPECTED TO BE RELATIVELY DRY.
CLOUDS SHOULD DEPART EASTERN UPPER/TIP OF THE MITT TOWARD MIDDAY...
WITH DECREASING CLOUDS (OUTSIDE OF DIURNAL CUMULUS DEVELOPMENT)
ACROSS THE REMAINDER OF NORTHERN LOWER DURING THE AFTERNOON.
ANOTHER COOL LATE AUGUST AFTERNOON (HIGHS IN THE MID 60S-LOWER 70S)
WILL BE FOLLOWED BY ANOTHER CHILLY NIGHT WITH GOOD RADIATIONAL
COOLING CONDITIONS EXPECTED (LOWS MOSTLY IN THE 40S...A FEW 30S IN
LOW LYING AREAS).

THURSDAY STARTS OUT SUNNY...BEFORE CLOUDS BEGIN TO SPREAD TOWARD
LOWER MICHIGAN FROM THE SOUTHWEST DURING THE AFTERNOON AS PRECIP
SPREADS INTO THE UPPER MISSISSIPPI VALLEY.  THINGS GET MORE
INTERESTING THURSDAY NIGHT...BUT HAVE A HUNCH THAT A LOT OF THE
ACTIVE WEATHER WILL REMAIN SOUTH AND SOUTHWEST OF THE FORECAST AREA.
CONVECTION EXPECTED TO FOCUS ALONG A SLOW MOVING WARM FRONT THAT
SETS UP ACROSS THE UPPER MISSISSIPPI VALLEY INTO SOUTHERN
WISCONSIN...AND CURRENT THINKING IS THIS IS WHERE MCS FORMATION IS
LIKELY.  NICE SURGE OF MOISTURE COMING NORTHEAST WITH PRECIPITABLE
WATER EXCEEDING 1.50 INCHES ALONG WITH GOOD WARM ADVECTION...BUT
CONVECTIVE PROPAGATION WILL LIKELY BE THE KEY TO RAINFALL POTENTIAL
ACROSS NORTHERN LOWER AND SUSPECT MUCH OF THE HEAVIER ACTIVITY MAY
SLIDE EAST TOWARD SOUTHERN LOWER MICHIGAN.  THIS WILL LEAVE NORTHERN
LOWER MOSTLY IN THE "STRATIFORM" AREA OF A POTENTIAL MCS...SO WILL
PAINT IN A POP GRADIENT FROM SOUTHWEST TO NORTHEAST...KEEPING FAR
EASTERN UPPER/NORTHEAST LOWER DRY THURSDAY NIGHT.  INITIAL STAB AT
RAINFALL TOTALS WILL CARRY 0.25-0.50 INCH ALONG-WEST OF THE M-37
CORRIDOR THROUGH DAYBREAK FRIDAY (THOUGH THIS VERY MUCH SUBJECT TO
CHANGE).

MEDIUM RANGE (FRIDAY/SATURDAY/SUNDAY): RAIN THREAT WILL CONTINUE
INTO FRIDAY WITH WHATEVER MCS REMNANTS WILL ROLL THROUGH PLUS
ADDITIONAL DEVELOPMENT WITHIN WARM ADVECTION/ISENTROPIC ASCENT
PATTERN.  SHOULD BE A PRETTY EFFICIENT RAIN PRODUCER EVEN IF THE
HEAVIER CELLS RIDE BY SOUTH OF THE FORECAST AREA GIVEN HIGH
PRECIPITABLE WATER AND POTENTIAL FOR A DEEP WARM CLOUD LAYER.
LOOKING INTO THE FIRST PART OF THE HOLIDAY WEEKEND...REMNANTS OF
SOUTHERN BRANCH SHORT WAVE TROUGH COMING OUT OF THE MIDWEST WILL BE
AN ISSUE WITH A LINGERING BAROCLINIC ZONE LYING ACROSS MICHIGAN
SERVING TO FOCUS ADDITIONAL SHOWERS AND THUNDERSTORMS.  SO NOT
LOOKING LIKE A GREAT START TO THE LABOR DAY WEEKEND IN GENERAL...
WILL JUST HAVE TO SEE WHERE WE CAN SQUEEZE IN SOME DRY PERIODS.

OUTLOOK (MONDAY/TUESDAY): APPROACHING COLD FRONT FOR LABOR DAY WILL
SET UP ANOTHER CHANCE FOR THUNDERSTORMS...ALONG WITH INCREASING
HUMIDITY.  FORECAST FOR THE START OF THE SCHOOL YEAR FOR MOST WILL
DEPEND ON FRONTAL TIMING...BUT WILL START WITH A CHANCE FOR
THUNDERSTORMS FOR NOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 127 PM EDT TUE AUG 26 2014

ANY LINGERING MVFR CIGS EARLY THIS AFTERNOON SHOULD GIVE WAY TO VFR
CONDITIONS AS LOW LEVEL DRYING CONTINUES. INCREASING HIGH/MID
CLOUDS LATER TONIGHT...WITH VFR CONDITIONS PREVAILING. SAME GOES
FOR WEDNESDAY MORNING. OCCASIONALLY GUSTY NORTHWEST WINDS THIS
AFTERNOON GO LIGHT THIS EVENING.

&&

.MARINE...
ISSUED AT 344 PM EDT TUE AUG 26 2014

SOMEWHAT GUSTY NORTHWEST WINDS EXPECTED TO CONTINUE INTO
THIS EVENING...BECOMING INCREASINGLY FOCUSED ACROSS LAKE HURON
OVERNIGHT AS SECONDARY LOW LEVEL SPEED MAX PUSHES ACROSS THE LAKE.
FAVORED NORTHEAST LOWER COASTAL CONVERGENCE WILL HELP THE
CAUSE...BUT STILL THINK ANY SCA WIND GUSTS WILL REMAIN ISOLATED
ENOUGH TO PRECLUDE A HEADLINE. NORTHWEST WINDS REMAIN GUSTY RIGHT
THROUGH WEDNESDAY ACROSS NORTHERN LAKE HURON AND WHITEFISH BAY...BUT
ONCE AGAIN SHOULD REMAIN JUST BELOW SCA CRITERIA. WINDS ARE EXPECTED
TO DIMINISH RATHER QUICKLY LATER WEDNESDAY NIGHT AS HIGH PRESSURE
BUILDS DIRECTLY OVERHEAD.

&&

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

&&

$$

SYNOPSIS...AM
SHORT TERM...MSB
LONG TERM...JPB
AVIATION...MSB
MARINE...MSB






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