Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 291748
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
148 PM EDT FRI MAY 29 2015

.UPDATE...
ISSUED AT 1014 AM EDT FRI MAY 29 2015

NOT A WHOLE LOT OF CHANGE FROM OVERNIGHT THINKING.
RATHER AGGRESSIVE SUB H8 MOISTENING CONTINUES TO STEADILY ADVECT
NORTH IN STRENGTHENING SOUTHERLY FLOW REGIME. DOWN LOW MOISTENING
AND NO INHIBITION THROUGH THE LOW/MID LEVELS WORKING TO KICK OFF
WIDELY SCATTERED SHOWERS ACROSS CENTRAL MICHIGAN. MORE CONCENTRATED
AREA OF SHOWERS/STORMS JUST TO OUR WEST TIED TO EMBEDDED WEAK WAVE
AND REMNANT LOW LEVEL JET AXIS. THIS BETTER FORCING LOOKS TO SLIDE
NORTHEAST...PERHAPS IMPACTING EASTERN UPPER MICHIGAN EARLY THIS
AFTERNOON. SAID MOISTURE ADVECTION SHOULD CONTINUE TO FIRE OFF
SCATTERED SHOWERS AND STORMS FURTHER SOUTH. AS FOR SEVERE
POTENTIAL...THREAT IS NOT ZERO. AREA REMAINS WITHIN SPC MARGINAL
CATEGORY FOR SUCH...WHICH IS FULLY SUPPORTED BY MODIFIED HIGH RES
SOUNDINGS SHOWING EFFECTIVE SHEAR AROUND 30 KNOTS AND ML CAPE
UPWARDS OF 1000 J/KG BY THIS AFTERNOON. MEAGER MID LEVEL LAPSE RATES
AND NOTHING TO EFFECTIVELY STOP QUICK DEVELOPMENT OF MOIST
CONVECTION SUPPORTS MORE OF A WIND THAN HAIL THREAT...WITH LOCALIZED
GUSTY WINDS TIED TO PRECIP LOADING AND USE OFF DEEPER SHEAR. PWAT
VALUES SURGING NORTH OF 1.30 INCHES AND SKINNY CAPE PROFILE THROUGH
THE MID LEVELS SUPPORTS SOME HEAVY RAIN POTENTIAL...ALTHOUGH STEADY
NORTHEAST MOVEMENT OF INDIVIDUAL CELLS SHOULD PRECLUDE ANY REAL
HEAVY RAINFALL AMOUNTS.

&&

.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 303 AM EDT FRI MAY 29 2015

...SHOWER AND THUNDERSTORM CHANCES INCREASING...

HIGH IMPACT WEATHER POTENTIAL...SCT THUNDERSTORMS THIS AFTERNOON
AND TONIGHT...MARGINAL CHANCE FOR SEVERE WX.

UPSTREAM COLD FRONT IS MOVING ACROSS NW MN AND EASTERN SD. THIS
FRONT WILL SLOWLY CROSS NORTHERN MI TONIGHT...IN FACT IT WILL NOT
QUITE EXIT BY 12Z. DEEP SW FLOW IN ADVANCE OF THE FRONT WILL BRING
AN INCREASINGLY MOIST AIRMASS INTO NORTHERN MI. A SURFACE WARM FRONT
IS ADVANCING INTO NORTHERN INDIANA/OHIO...THIS WILL LIFT INTO
SOUTHERN SECTIONS OF THE FORECAST AREA BY MIDDAY.

THIS MORNING...SHARP SUB-850MB THETA-E ADVECTION ARRIVES IN SOUTHERN
SECTIONS BEGINNING AT 09Z...A BIT AHEAD OF THE SURFACE WARM FRONT.
THIS SOUPIER AIRMASS WILL RESULT IN ELEVATED MARGINAL INSTABILITY...
WITH MUCAPES INCREASING TO 300-500J/KG IN SOUTHERN SECTIONS. MODELS
ARE GENERALLY INCLINED TO POP SOME SHRA IN MUCH OF NORTHERN LOWER...
WHICH IS PERHAPS A BIT OVERDONE GIVEN LIMITED PROGRESS OF RICH THETA-
E AIR. BUT A SMALL CHANCE OF MORNING SHRA SOUTH OF M-32 IS
REASONABLE. WILL NOT MENTION ANY THUNDER.

THIS AFTERNOON/EVENING...SO HOW MUCH INSTABILITY CAN WE DEVELOP THIS
AFTERNOON? SW LOW-LEVEL FLOW WILL LIMIT INSTABILITY NEAR LAKE MI IN
NW LOWER MI...AND IN MOST OF EASTERN UPPER. BUT MLCAPE SHOULD
QUICKLY SHOOT UP TOWARD 1K J/KG BY EARLY/MID AFTERNOON ALONG/E OF US-
131 IN NORTHERN LOWER. THIS IS UNCAPPED (A SLIGHT WARM NOSE AT 925
IS UNLIKELY TO SURVIVE PAST 18Z)...AND ANY LITTLE BOUNDARY WILL SET
THINGS OFF. THIS ALSO SUGGESTS WE WILL STRUGGLE TO BUILD CAPE MUCH
PAST THAT W/O DEVELOPING DEEP CONVECTION. WILL HAVE SCT PRECIP
ACROSS THE REGION THIS AFTERNOON AND EVENING. 0-6KM BULK SHEAR IN
THE 30-40KT RANGE IS HEALTHY BUT NOT OFF THE CHARTS. HODOGRAPH IS
NOT QUITE A STRAIGHT LINE...GENERALLY SSW WINDS AT THE SURFACE AND
SW ALOFT...BUT SHEAR IS DEFINITELY MORE SPEED AND LESS DIRECTIONAL.
MAY BE A TENDENCY FOR SOMEWHAT BACKED SURFACE WINDS IN NE LOWER...
WHICH WOULD AMP UP LOW-LEVEL SHEAR. BUT IN GENERAL... SHEAR/
INSTABILITY PROGS SUPPORT MULTICELL CLUSTERS AND PERHAPS SOME
SUPERCELLS AT TIMES. THE LATTER WOULD CERTAINLY RESULT IN AN
ISOLATED WIND/PERHAPS HAIL THREAT. THIS IS IN LINE WITH THE SPC
OUTLOOK FOR THE AREA.

MAX TEMPS 70S TO LOWER 80S.

OVERNIGHT...MOST WIDESPREAD PRECIP SEEMS LIKELY OVERNIGHT...AS THE
SURFACE COLD FRONT AND BROADER FORCING FOR ASCENT ARRIVES.
INSTABILITY WILL BE WANING BY THEN...LOWERING BELOW 1K J/KG OF
MUCAPE. THIS WILL LIMIT SVR POTENTIAL...BUT HIGH LIKELY TO
CATEGORICAL POPS ARE IN ORDER FOR THE OVERNIGHT.

MIN TEMPS RANGE FROM UPPER 40S EASTERN UPPER TO MID 60S NEAR SAGINAW
BAY.

&&

.SHORT TERM...(SATURDAY THROUGH SUNDAY NIGHT)
ISSUED AT 303 AM EDT FRI MAY 29 2015

HIGH IMPACT WEATHER POTENTIAL: FROST CONCERNS BOTH SATURDAY AND
SUNDAY NIGHTS. COULD BE LOOKING AT SOME OF THE USUAL COLDER
SPOTS SEEING A HARD FREEZE (28F OR LOWER) ONE OR BOTH NIGHTS.

WELL...THE MONTH OF MAY IS ON ITS WAY OUT...AND WE ARE EXCITED TO
WELCOME THE START OF METEOROLOGICAL SUMMER ON JUNE 1ST. WHAT BETTER
WAY TO CELEBRATE THAN TO TALK ABOUT FROST AND/OR FREEZE ISSUES?
WAIT...WHAT?!?! SADLY...AS MANY LONGTIME RESIDENTS OF NORTHERN
MICHIGAN KNOW ALL TOO WELL...THIS PLACE IS PRONE TO SOME CHILLY
TEMPERATURES AT JUST ABOUT ANY POINT IN THE YEAR...AND IT WOULD
APPEAR WE ARE IN FOR ANOTHER BOUT OF CANADIAN COOLNESS AS WE PUSH
THROUGH THE WEEKEND AND EARLY NEXT WEEK. IN THIS CASE...THE CULPRIT
IS OUR OLD FRIEND JAMES BAY HIGH PRESSURE...PROGGED TO NOSE INTO THE
REGION IN THE WAKE OF FRIDAY NIGHT`S FRONTAL PASSAGE AND STICK
AROUND FOR QUITE SOME TIME. FOR US METEOROLOGISTS...THIS IS A REALLY
SIMPLE PATTERN...AS THERE WILL BE BASICALLY NO CHANCE FOR RAIN
COURTESY OF SOME VERY DRY AIR...MINUS THE POSSIBILITY FOR SOME PESKY
SHOWERS TO LINGER FOR A TIME INTO SATURDAY.

AS HAS BEEN DISCUSSED OVER RECENT DAYS...QUITE THE AIRMASS CHANGE
FIRST THING SATURDAY WILL SEND THE ATMOSPHERE FOR A LOOP...WITH A
TIGHT AXIS OF LOW/MID LEVEL FRONTOGENESIS WORKING ACROSS NORTHERN
MICHIGAN.. THAT FEATURE WILL FIND ITSELF INCREASINGLY DRIVEN INTO
THE LOWER LAKES AS OUR ABOVE-MENTIONED HIGH PRESSURE SYSTEM FLEXES
ITS MUSCLE...AND SOME VERY DRY AIR (PWAT VALUES DOWN BELOW 0.30
INCHES) ROLLS IN QUICKLY FROM NORTH TO SOUTH. SAID FGEN FORCING
WORKING IN TANDEM WITH INITIAL REMNANT DEEPER MOISTURE WILL LIKELY
TRY TO KEEP A BAND OF RAIN GOING FOR MUCH OF NORTHERN LOWER MICHIGAN
SATURDAY MORNING...THOUGH TO BE PERFECTLY HONEST...THERE IS STILL A
TOUCH OF LOWER CONFIDENCE ON THE NORTHERN EXTENT OF THIS FEATURE.
THE ECMWF HAS BEEN QUITE INSISTENT ON THE PLACEMENT OF A WEAKISH
SHORTWAVE FEATURE HELPING EXTEND THE RAIN CHANCE A BIT LONGER IN THE
DAY...AND GIVEN THE SETUP (AND LOTS OF EXPERIENCE WITH SIMILAR
EVENTS OVER THE YEARS)...WOULDN`T BE SHOCKED IF RAIN DID INDEED TAKE
A FEW MORE HOURS TO EXIT THE AREA.

THAT WILL ALL BE HISTORY BY LATE SATURDAY AFTERNOON AND EVENING...AS
STRONG DRYING IN THE WAKE OF THE FRONT RAPIDLY CLEARS SKIES OUT.
THAT SETUP...IN COMBINATION WITH THE ARRIVAL OF PRONOUNCED THERMAL
TROUGHING (H8 TEMPS SLIDING TOWARD 0-2C) SHOULD SET THE STAGE FOR A
COOL NIGHT. DESPITE RECENT RAINFALL...AN INFLUX OF VERY DRY DEW
POINTS SHOULD OFFSET THE WET SOILS...THOUGH WOULDN`T BE SHOCKED IF
WE ULTIMATELY END UP WITH A LITTLE BIT OF FOG IN SPOTS. FROST
CONCERNS ALSO ARISE SIMPLY GIVEN THE MAGNITUDE OF THE COOLER AIR
ARRIVING...THOUGH AS MENTIONED YESTERDAY...WE DO LOOK TO HAVE A BIT
OF A LINGERING GRADIENT FOR MOST OF THE NIGHT...ESPECIALLY FOR AREAS
SOUTH OF M-72. NONETHELESS...HAVE NO DOUBT THE USUAL SUSPECT SITES
WILL DECOUPLE AND HAVE A CHANCE TO CRASH THROUGH THE LOWER 30S...AND
PERHAPS EVEN UPPER 20S. A COLD START SHOULD GIVE WAY TO A SUNNY BUT
STILL COOLISH SUNDAY...BUT WITH AN EVEN BETTER SETUP FOR FROST/
FREEZE ISSUES FOR SUNDAY NIGHT AS THE LOW LEVEL RIDGE AXIS PARKS
ITSELF OVERHEAD. GUIDANCE NUMBERS CONTINUE TO TREND COLDER EACH
RUN...WITH LITTLE DOUBT WE WILL EVENTUALLY NEED ANOTHER ROUND OF
FROST/FREEZE HEADLINES. SIMPLY PUT...IF YOU HAVEN`T PLANTED YOUR
GARDEN YET...HANG TIGHT FOR A FEW MORE DAYS!


&&

.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 303 AM EDT FRI MAY 29 2015

A RATHER QUIET STRETCH OF WEATHER TO START THE WORK WEEK (AND
WELCOME THE MONTH OF JUNE)...AS HIGH PRESSURE HOLDS FIRM THROUGH AT
LEAST TUESDAY NIGHT. BASED ON THE PLACEMENT OF THE RIDGE AXIS
OVERHEAD ONCE AGAIN MONDAY NIGHT...PROBABLY LOOKING AT ANOTHER
CHANCE FOR FROST IN MANY INLAND AREAS...BUT WITH AN OVERALL GRADUAL
UPWARD TREND IN TEMPERATURES INTO MIDWEEK. BETTER MOISTURE RETURN
WRAPPING AROUND THE PERIPHERY OF THE DEPARTING HIGH BY WEDNESDAY MAY
BRING A SHOT AT SOME SHOWERS FOR AREAS OVER THE EASTERN U.P. WITH
MAYBE (THAT`S A BIG MAYBE) A LITTLE BETTER SHOT FOR ALL AREAS BY
THURSDAY. HOWEVER...HISTORY TIME AND AGAIN IN THESE SETUPS STRONGLY
ARGUES OUR LOCAL AIRMASS WILL REMAIN ON THE DRY SIDE AS WE STILL
MAINTAIN SOME WEAK SEMBLANCE OF LOW LEVEL RIDGING...WITH MY GUT
FEELING MOST IF NOT ALL AREAS WILL REMAIN DRY INTO THURSDAY NIGHT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 142 PM EDT FRI MAY 29 2015

DIFFICULT FORECAST REGARDING CONVECTIVE EVOLUTION THROUGH EARLY
THIS AFTERNOON. AIRMASS HAS DESTABILIZED...KICKING OFF CONVECTION
AT THIS HOUR. NICE LINE SEGMENT HAS FORMED EAST OF TVC...WHICH
MAY HOLD TOGETHER RIGHT ACROSS NORTHERN MICHIGAN. OTHERWISE...
ADDITIONAL ACTIVITY CONTINUES TO FIRE IN AN INCREASINGLY MOIST
AIRMASS. HAVE TRIED SOME TIMING AT ALL SITES...WITH JUST SOME
LOWER END IMPACTS UNTIL CONVECTIVE EVOLUTION IS BETTER REALIZED.
ANY STORM WILL BE CAPABLE OF VERY HEAVY RAIN AND BRIEF GUSTY
WINDS...ALTHOUGH LIKELY REMAINING BELOW SEVERE LIMITS. COLD FRONT
SLOWLY CROSSES THE AREA OVERNIGHT...BRINGING WIDESPREAD RAIN AND
IFR CIGS AS COOL SURFACE AIR UNDERCUTS STILL WARM AIR ALOFT. GUSTY
NORTHWEST/NORTH WINDS SATURDAY WITH LINGERING LOW OVERCAST AND
RAINS.

&&

.MARINE...
ISSUED AT 303 AM EDT FRI MAY 29 2015

LIGHT SOUTHERLY WINDS THRU THIS EVENING...AHEAD OF A COLD FRONT
THAT ENTERS THE REGION OVERNIGHT AND EXITS LATER ON SATURDAY. SOME
FOG POTENTIAL AS AIRMASS GETS MORE HUMID UNTIL THE FRONT PASSES.
WINDS REMAIN RELATIVELY LIGHT INTO THE OVERNIGHT HOURS...BUT PICK
UP FROM THE N TO NW ON SATURDAY...ESPECIALLY ON LAKE MI. SMALL
CRAFT ADVISORIES MAY EVENTUALLY BE NEEDED.


&&

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

$$

UPDATE...MSB
NEAR TERM...JAZ
SHORT TERM...LAWRENCE
LONG TERM...LAWRENCE
AVIATION...MSB
MARINE...JAZ



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