Area Forecast Discussion
Issued by NWS Gaylord, MI

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315
FXUS63 KAPX 171916
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
316 PM EDT SUN MAY 17 2015

.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 310 PM EDT SUN MAY 17 2015

HIGH IMPACT WEATHER POTENTIAL: SLIGHT CHANCE FOR SEVERE
THUNDERSTORMS LATE THIS AFTERNOON AND EARLY EVENING.

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: WARM FRONT HAS MIXED
NORTHWARD QUICKLY...NOW STUCK IN ITS CLIMATOLOGICAL FAVORED AREA
OF THE STRAITS. INCREASED MIXING HAS SCOURED OUT EARLY
STRATUS...REPLACED BY MOSTLY CU AND OVERSPREADING CIRRUS.
TEMPERATURES HAVE WARMED NICELY SOUTH OF THE WARM FRONT...WITH
READINGS LARGELY IN THE 70S SOUTH OF THE BRIDGE. COMBINATION OF WARM
TEMPS AND SOME RATHER RESPECTABLE DEW POINTS (LOWER/MID 60S)
ACTUALLY MAKING IT FEEL QUITE SUMMER-LIKE. ABOVE DRIVEN BY A RATHER
AMPLIFIED PATTERN...WITH OVERHEAD RIDGING BEGINNING TO SHOW SIGNS OF
SUCCUMBING TO ROBUST NORTHERN PLAINS SHORTWAVE. STRONG SURFACE LOW
COLLOCATED WITH THIS LATTER FEATURE...WITH WELL DEVELOPED COLD
FRONT/DRY LINE EXTENDING SOUTH INTO THE SOUTHERN PLAINS. MAIN AREA
OF RAIN TIED TO UPPER LEVEL WAVE ITSELF...WITH ANOTHER AREA
CONCENTRATED WELL OFF TO OUR SOUTH IN VICINITY OF DEEPER MOISTURE
AND REMNANT BOUNDARIES FROM LAST NIGHT`S CONVECTIVE EPISODE. JUST
SEEING SOME SIGNS OF ACTIVITY BREAKING OUT INTO THE FAR WESTERN
LAKES VIA APPROACHING MID LEVEL SPEED MAXIMA/EMBEDDED VORT LOBES
ROTATING AROUND PARENT SYSTEM. GRADUALLY FALLING MID LEVEL HEIGHTS
AND APPROACH OF THESE EMBEDDED VORT LOBES SHOULD PROVIDE THE IMPETUS
TO KICK OFF A FEW SHOWERS AND STORMS ACROSS OUR NECK OF THE WOODS
LATER TODAY AND THIS EVENING. DEVELOPMENT OF MARGINAL DEEP LAYER
SHEAR PROVIDING SOME POSSIBILITY A FEW OF THESE STORMS MAY BECOME
SEVERE.

PRIMARY FORECAST CONCERNS/CHALLENGES: ADDRESSING CONVECTIVE
EVOLUTION AND SEVERE WEATHER POSSIBILITIES THROUGH THIS EVENING.

DETAILS: STILL ONE TOUGH FORECAST HEADING INTO THIS EVENING AS ALL
REAL DEEP LAYER DYNAMICS REMAIN FOCUSED WELL OFF TO OUR WEST.
WARMING AIRMASS JUST SHOWING SIGNS OF DESTABILIZING...WITH UPWARDS
OF 1000 J/KG OF SURFACE BASED CAPE NOTED ON LATEST SPC ANALYSIS. CU
REMAINS UNIMPRESSIVE...LIKELY A RESULT OF REMAINING CINH ALSO NOTED
ON ANALYSIS. ALL HIGH RES GUIDANCE SUGGESTS THIS INHIBITION BEING
OVERCOME LATER THIS AFTERNOON SOUTHWEST OF TVC WITH APPROACH OF VORT
LOBE AND INCREASES LOW LEVEL SURFACE CONVERGENCE. A DISJOINTED LINE
OF SHOWERS AND STORMS SHOULD ADVANCE STEADILY EAST...LIKELY MAXING
OUT IN INTENSITY RATHER QUICKLY BEFORE DAYTIME INSTABILITY BEGINS TO
WANE. MARGINAL PARAMETERS FOR SEVERE WEATHER ACROSS OUR AREA...WITH
RATHER LIMITED INSTABILITY/SUB 6C MID LEVEL LAPSE RATES/AND GREATEST
SHEAR REMAINING UPSTREAM. SPC HAS TRIMMED EARLIER EXTENSION OF
SLIGHT RISK...WITH ITS EASTERN FLANK NOW JUST SKIMMING PART OF
LEELANAU/BENZIE/AND MANISTEE COUNTIES...WITH THE MARGINAL CATEGORY
SEVERAL COUNTIES FURTHER EAST. THEY...LIKE US...OUR NOT TOTALLY SOLD
ON THE IDEA OF ANY SEVERE WEATHER FOR NORTHERN MICHIGAN.
STILL...JUST ENOUGH PARAMETERS THERE TO ALLOW FOR A FEW ISOLATED
SEVERE WIND GUSTS OR MARGINALLY SEVERE HAIL THIS EVENING.

FRONT REMAINS WELL UPSTREAM TONIGHT...SUGGESTING THIS EVENINGS
ACTIVITY WILL BE ABOUT IT. SUPPOSE SOME UPSTREAM SHOWERS MAY MAKE A
RUN AT OUR AREA OVERNIGHT...BUT THEY WILL STRUGGLE TO DO SO WITH
LOSS OF INSTABILITY.

&&

.SHORT TERM...(MONDAY THROUGH WEDNESDAY)
ISSUED AT 310 PM EDT SUN MAY 17 2015

HIGH IMPACT WEATHER POTENTIAL: FROST TUESDAY NIGHT.

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION:  UPPER LOW GRADUALLY DAMPENS
OUT AND WEAKENS AS IT SLIDES ACROSS LAKE SUPERIOR.  AT THE SAME
TIME...SURFACE LOW MOVES THROUGH SOUTHERN CANADA HELPING TO SWING A
STRONG COLD FRONT ACROSS THE NORTHERN LAKES AND USHERING IN FALL-
LIKE TEMPERATURES FOR THE MIDWEEK PERIOD.

PRIMARY FORECAST CONCERNS/CHALLENGES: LOW PRECIPITATION CHANCES
MONDAY NIGHT/TUESDAY.  FROST POTENTIAL TUESDAY NIGHT.

EARLY MORNING LOW CLOUDS MONDAY MORNING WILL MIX TO PARTLY SUNNY
SKIES AS THE DAY PROGRESSES.  FAIRLY EXPANSIVE PRE-FRONTAL DRY SLOT
ACROSS NORTHERN MICHIGAN ON TUESDAY...WITH PWATS DROPPING TOWARD
0.75 INCHES IN MOST AREAS WITH MEAN RH OF LESS THAN 35% IN THE H8-H5
LAYER. SLIGHTLY HIGHER PWATS/MOISTURE UP ALONG THE IMMEDIATE LAKE
HURON COASTLINE ALIGNED WITH WEAK H8-H7 THETA-E RIDGE.  ALONG THE
LAKE HURON COAST...VERY SKINNY CAPE AND LIMITED FORCING...SO
DIFFICULT TO SEE MUCH OF ANYTHING DEVELOPING OUTSIDE A BIT MORE
CU...AND WILL LEAVE FORECAST DRY.  THERE MAY BE AN ISOLATED SHOWER
OVER PARTS OF EASTERN UPPER DURING THE AFTERNOON AS DEEPER MOISTURE
ASSOCIATED WITH UPPER LOW AND IN ADVANCE OF COLD FRONT MOVE INTO THE
AREA.  ANOTHER WARM DAY...WITH WIDESPREAD 70S AND 80S.

FRONT COMES THROUGH MONDAY NIGHT USHERING IN MUCH COOLER AREA.
LIKELY A DRY FROPA FOR MOST AREAS...WITH LITTLE IN THE WAY OF
MOISTURE.  EXCEPTION MAY BE EASTERN UPPER WHERE MOISTURE/FORCING
WILL BE A BIT MORE FAVORABLE FOR A FEW SHOWERS.  FOR THE WARM
WEATHER LOVERS...YOU SHOULD SKIP TO THE LONGER TERM SECTION OF THE
FORECAST AT THIS POINT.  UNSEASONABLY COOL THERMAL TROUGH OVER THE
GREAT LAKES ON TUESDAY WITH PLENTY OF SUB H8 MOISTURE...GUSTY
NORTHWEST WINDS AND TEMPERATURES IN THE 40S /WIND CHILL TEMPS IN THE
30S/.  WE WILL LIKELY CHALLENGE SOME RECORD LOW MAX TEMPS IN SOME
LOCALES.

FROST POTENTIAL TUESDAY NIGHT DEPENDENT LARGELY ON CLEARING SKIES
AND WINDS.  SKIES SHOULD CLEAR FROM WEST-EAST AND GRADIENT WILL
GRADUALLY SLACKEN.  BIG QUESTION IS...HOW QUICKLY.  TEMPERATURES
WILL NOT HAVE FAR TO FALL FROM DAYTIME "HIGHS" IN THE 40S...AND LOW
TEMPERATURES INTO THE 20S TO LOWER 30S A GOOD POSSIBILITY.  IF
CLEARING AND LIGHTER WINDS OCCUR EARLIER...WIDESPREAD 20S A
POSSIBILITY.  CERTAINLY A NIGHT WHERE FROST/FREEZE HEADLINES A GOOD
POSSIBILITY. QUIET WEATHER ON WEDNESDAY WITH HIGH TEMPERATURES
MODIFYING BACK INTO THE 50S UNDER LOTS OF SUNSHINE.

&&

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 310 PM EDT SUN MAY 17 2015

THINGS LOOK PRETTY BENIGN FOR MOST OF THE EXTENDED PERIOD. HIGH
PRESSURE WILL BUILD INTO THE REGION THROUGH THE WEEKEND WHEN IT WILL
BE CENTERED OVER MICHIGAN. AHEAD OF THE HIGH PRESSURE CENTER...CLEAR
SKIES AND N/NW FLOW COULD BRING SOME FROST CONCERNS FOR LOW LYING
AREAS...THOUGH TUESDAY NIGHT STILL LOOKS TO BE THE COLDEST OF THE
WEEK. AS THE FLOW BECOMES MORE SOUTHERLY SATURDAY BEHIND THE EXITING
HIGH...TEMPERATURES WILL BEGIN TO GET BACK TOWARD NORMAL FOR THIS
TIME OF YEAR IN THE MID TO UPPER 60S. THERE IS A CHANCE OF SOME
SHOWERS SUNDAY AHEAD OF A WARM FRONT ASSOCIATED WITH LOW PRESSURE
MOVING OUT OF THE PLAINS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 135 PM EDT SUN MAY 17 2015

WARM...INCREASING HUMID AIRMASS RESULTING IN THE DEVELOPMENT OF
SOME STCU/CU THIS AFTERNOON. STILL EXPECTING BROKEN LINE OF
SHOWERS/STORMS TO DEVELOP SOUTH OF TVC THIS AFTERNOON...WORKING
EAST ACROSS THE TAF SITES LATER THIS AFTERNOON AND EVENING. HAVE
TRIED SOME SPECIFIC TIMING...TARGETING IMPACTS FOR A 2 HOUR WINDOW
AT EACH TAF SITE. EXPECT MVFR CIGS/VIS AS THESE SHOWERS PASS
OVERHEAD. WILL NOT INCLUDE ANY SPECIFIC WIND GUSTS JUST YET DURING
THEIR PASSAGE...ALTHOUGH SOME VERY GUSTY WINDS ARE POSSIBLE.
DRYING SHOULD FOLLOW...ALTHOUGH WITH SSE FLOW OFF LAKE
HURON...WOULD EXPECT THE DEVELOPMENT OF MORE STRATUS AT APN
OVERNIGHT. OTHERWISE...VFR CONDITIONS EXPECTED. DRY WEATHER
TOMORROW UNDER INCREASINGLY GUSTY SOUTHWEST WINDS.


&&

.MARINE...
ISSUED AT 310 PM EDT SUN MAY 17 2015

WINDS WILL INCREASE IN SPEED OUT OF THE SOUTH TONIGHT AS LOW
PRESSURE PULLS THROUGH THE NORTHERN PLAINS INTO CANADA. WINDS WILL
GRADUALLY VEER MORE SOUTHWEST MONDAY...BECOMING QUITE GUSTY
THROUGH THE DAY. CURRENT INDICATIONS ARE MOST AREAS SHOULD REMAIN
BELOW SCA CRITERIA...ALTHOUGH IT MAY BE CLOSE ON LAKE MICHIGAN.
WEST TO NORTHWEST WINDS MONDAY NIGHT AND TUESDAY...REMAINING
GUSTY.

THUNDERSTORMS ARE POSSIBLE LATE THIS AFTERNOON AND EVENING...WITH
ISOLATED GUSTY WINDS AND EVEN THE THREAT FOR SMALL HAIL WITH ANY
STRONGER STORMS.

&&

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

$$

NEAR TERM...MSB
SHORT TERM...KEYSOR
LONG TERM...ALM
AVIATION...MSB
MARINE...MSB



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