Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 300133
AFDAPX

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

.UPDATE...
ISSUED AT 933 PM EDT FRI MAY 29 2015

OVERVIEW: EVENING SFC ANALYSIS REVEALS A STRETCHED OUT COLD FRONT
AND NARROW CORRIDOR OF CONVECTION FROM EASTERN UPPER MICHIGAN DOWN
THROUGH EASTERN WISCONSIN INTO IOWA. UPPER AIR ANALYSIS REVEALS A
STRENGTHENING UPPER JET STREAK ACROSS THE NRN LAKES WITH A BATCH
OF POST-FRONTAL RAINFALL ACROSS NRN WISCONSIN MOIVING INTO WESTERN
UPPER MICHIGAN.

AHEAD OF THE FRONT...A FAIRLY WARM AND HUMID AIRMASS IS IN PLACE
WITH DEWPOINTS SPANNING THE 60S. SEVERAL POCKETS OF SHOWERS AND A
FEW STORMS CONTINUE TO RUN UP THROUGH LOWER MICHIGAN AHEAD OF THE
FRONT...ONE EXITING THE LAKE HURON COAST AND A SECOND MOVING UP
THROUGH THE SW COUNTIES OF THIS CWA. STORMS HAVE BEEN FAIRLY
BENIGN.

REST OF THE NIGHT...POCKETS OF SHOWERS/SOME THUNDER WILL CONTINUE
TO IMPACT NRN LOWER MICHIGAN FOR THE REST OF THE EVENING...WHILE
NARROW CORRIDOR OF SHOWERS/SOME THUNDER ADVANCES INTO EASTERN
UPPER. COLD FRONT AND ATTENDING LINE OF SHOWERS WILL SAG DOWN
THROUGH NRN LOWER MICHIGAN DURING THE OVERNIGHT HOURS...ROUGHLY
06Z TO 12Z...ALSO BRINGING A PERIOD OF LOW CLOUD COVER AND
PERHAPS SOME FOG AS A COOLER AIRMASS UNDERCUTS THE WARMER/HUMID
AIRMASS CURRENTLY IN PLACE. IN ADDITION...STILL ANTICIPATE
FURTHER DEVELOPMENT OF WIDESPREAD POST-FRONTAL RAINFALL OVERNIGHT
AS AFOREMENTIONED UPPER JET STREAK BEHIND THE FRONT STRENGTHENS
AND SLIDES UP THROUGH LAKE SUPERIOR. GOING FORECAST PRETTY MUCH
HAD THIS IDEA WITH JUST COSMETIC TWEAKS MADE ON MY PART.

&&

.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 407 PM EDT FRI MAY 29 2015

HIGH IMPACT WEATHER POTENTIAL: THUNDERSTORMS WITH BRIEF HEAVY RAIN
AND GUSTY WINDS THIS EVENING.

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: WARM AND MOIST AIRMASS IN
PLACE ACROSS THE NORTHERN LAKES AT THIS HOUR...COURTESY OF DEEP
SOUTHERLY FLOW AHEAD OF DIGGING UPSTREAM WAVE AND ATTENDANT
DEVELOPING NORTHERN PLAINS COLD FRONT. COMBINATION OF
MOISTURE/WARMTH HAS DESTABILIZED THE NORTHERN MICHIGAN
AIRMASS...WITH SEVERAL HUNDRED JOULES/KG OF MEAN LAYER CAPE NOTED ON
LOCAL ANALYSIS. INITIAL VORT LOBE/CONGEALED COLD POOLS FROM EARLIER
UPSTREAM CONVECTION HELPED IGNITE A RATHER VIGOROUS LINE OF SHOWERS
AND STORMS ACROSS NORTHERN LOWER MICHIGAN...ACCOMPANIED BY BRIEF
VERY HEAVY RAIN AND GUSTY WINDS. LIMITED INSTABILITY/WEAK MID LEVEL
LAPSE RATES HAVE REALLY CONFINED ALL INTENSE CORES TO THE LOWER
LEVELS...NEGATING ANY SEVERE WEATHER. STRONG...BUT BRIEF...
SUBSIDENCE REGIME IMMEDIATELY BEHIND THIS LINE HELPING QUELL ANY
ADDITIONAL SHOWER DEVELOPMENT AT THIS TIME ACROSS NORTHWEST LOWER.

ABOVE PATTERN REMAINS PROGRESSIVE TONIGHT...WITH UPSTREAM COLD FRONT
MAKING SLOW BUT STEADY PROGRESS SOUTHEAST ACROSS OUR AREA THIS
EVENING AND OVERNIGHT...KICKING OFF ADDITION RAIN CHANCES AS IT DOES
SO.

PRIMARY FORECAST CONCERNS/CHALLENGES: TEMPORAL AND SPATIAL
RESOLUTION OF SHOWERS AND STORMS TONIGHT. ADDRESSING LOW END SEVERE
CHANCES THIS EVENING.

DETAILS: TWO PART PROCESS FOR ADDITIONAL RAIN CHANCES TONIGHT.
ADDITIONAL CONVECTIVE DEVELOPMENT EXPECTED LATER THIS AFTERNOON AND
INTO THE EVENING WITHIN MARGINALLY UNSTABLE ENVIRONMENT AHEAD OF
APPROACHING COLD FRONT. WITH THAT SAID...WELL ORGANIZED SUBSIDENCE
REGIME WEST OF ONGOING LINE OF CONVECTION MAY SUPPRESS THINGS FOR A
WHILE...EVENING PERHAPS ALLOWING SOME BRIEF CLEARING BEFORE THE SUN
SETS. WOULD EXPECT BEST FOCUS FOR ADDITIONAL ACTIVITY INTO EARLY
THIS EVENING TO BE FOUND ACROSS NORTHEAST LOWER MICHIGAN. NOT
EXPECTING ANY SEVERE WEATHER WITH MARGINAL INSTABILITY AND LIMITED
MID LEVEL LAPSE RATES CONTINUING TO SUPPRESS ELEVATED CORE
POTENTIAL. DEEP MOISTURE ARGUES FOR PERIODS OF VERY HEAVY
RAIN...WITH ATTENDANT WET MICROBURSTS POTENTIALLY BRINGING SOME
GUSTY WINDS. OF COURSE...NOT COMPLETELY IMPOSSIBLE FOR ONE OF THESE
WIND GUSTS TO REACH SEVERE LIMITS...ALTHOUGH THAT SHOULD DEFINITELY
BE MORE OF THE EXCEPTION THAN THE RULE.

MORE WIDESPREAD RAINS DEVELOP LATER TONIGHT FROM NORTH TO
SOUTH...OCCURRING BEHIND ACTUAL FRONT IN REGION OF INTENSIFYING RER
UPPER JET DYNAMICS AND ATTENDANT INCREASING FGEN SIGNATURES. BEST
MOISTURE INFLOW BECOMES INCREASINGLY LOST...BUT DYNAMICS DEFINITELY
THERE TO SUPPORT WIDESPREAD LIGHT TO MODERATE RAINS. WILL ATTEMPT
SOME TIMING OF THIS STEADIER RAIN POTENTIAL...SWIPING CATEGORICAL
POPS FROM NORTHWEST TO SOUTHEAST THROUGH THE LATE NIGHT.

&&

.SHORT TERM...(SATURDAY THROUGH MONDAY)
ISSUED AT 407 PM EDT FRI MAY 29 2015

...SPLIT WEEKEND WITH WET WEATHER SATURDAY/DRY AND COOL SUNDAY...

HIGH IMPACT WEATHER POTENTIAL: FROST POTENTIAL ESPECIALLY SUNDAY
NIGHT/MONDAY MORNING.

PATTERN SYNOPSIS/FORECAST: LARGE SCALE PATTERN PROGRESSES FROM
TROUGHING IN THE VICINITY OF THE DATELINE...TO A SPLIT/BLOCKY
(STRONG -EPO) PATTERN OVER THE EASTERN PACIFIC WITH THIS SPLIT FLOW
CONTINUING DOWNSTREAM INTO NORTH AMERICA.  NORTHERN BRANCH FLOW
CONFINED NORTH OF THE BORDER...WITH WEAKER SOUTHERN BRANCH FLOW
ENCOMPASSING THE LOWER 48.  WELL-DEFINED SHORT WAVE ENERGY IN THE
NORTHERN BRANCH OVER MANITOBA/SASKATCHEWAN DIGGING SOUTHEAST...WITH
A SOUTHERN BRANCH SHORT WAVE TROUGH ROLLING INTO NEBRASKA/KANSAS...
WITH ANOTHER OVER EASTERN TEXAS.  AFTERNOON SURFACE ANALYSIS SHOWS A
STRONG COLD FRONT EXTENDING FROM A SURFACE LOW OVER NORTHWEST
ONTARIO...ACROSS MINNESOTA AND INTO NORTHWEST NEBRASKA.  MOISTURE
SURGING NORTH AHEAD OF THE COLD FRONT WITH 60S DEW POINTS INTO
WISCONSIN/LOWER MICHIGAN AND PRECIPITABLE WATER VALUES OF 1.00-1.50
INCHES.

HEIGHT FALLS ASSOCIATED WITH NORTHERN BRANCH SHORT WAVE TROUGH
FORECAST TO "SCRAPE" BY THE UPPER LAKES SATURDAY...WITH A GENERALLY
PACIFIC-DOMINATED ZONAL FLOW ACROSS THE NORTHERN TIER OF STATES/
GREAT LAKES FOR SUNDAY WITH FORECAST TRENDING TOWARD ANOTHER
DEVELOPING SHORT WAVE TROUGH OVER THE UPPER LAKES FOR MONDAY.
NORTHERN BRANCH WAVE WILL PUSH THE UPSTREAM COLD FRONT ACROSS LOWER
MICHIGAN SATURDAY...WITH AN UNSEASONABLY STRONG 1028+MB SURFACE HIGH
BUILDING INTO MICHIGAN FOR SUNDAY...WITH LOW LEVEL RIDGING HANGING
ON FOR MONDAY AS HIGH CENTER MOVES INTO QUEBEC.

PRIMARY FORECAST CONCERNS:  RAIN SATURDAY WINDING DOWN FROM NORTH TO
SOUTH...LOW TEMPERATURES SUNDAY MORNING AND POSSIBLE IMPACTS OF A
LINGERING WIND OVERNIGHT.

SATURDAY...COLD FRONT WILL BE PUSHING THROUGH SOUTHEAST PORTION OF
THE FORECAST AREA AT DAYBREAK...WITH RAIN ONGOING ACROSS MOST OF THE
FORECAST AREA IN POST-FRONTAL AIR MASS...WITHIN FRONTAL CIRCULATION
AND AIDED BY JET ENTRANCE REGION FORCING.  SOME DIFFERENCES IN
TIMING THE BACK EDGE OF THE RAIN SHIELD DURING THE DAY SO WILL
PROBABLY COMPROMISE/SMOOTH SOME OF THESE DIFFERENCES WHICH WILL
TREND KEEPING RAIN GOING A LITTLE LONGER IN SPOTS.  RAIN PROBABLY
WON`T END NEAR SAGINAW BAY UNTIL CLOSER TO SUNDOWN.  RAINFALL
AMOUNTS GREATER THAN A QUARTER-INCH EXPECTED SOUTH OF M-32
SATURDAY...AND PERHAPS HALF TO THREE-QUARTERS OF AN INCH OF RAIN
SOUTH OF A HOUGHTON LAKE-HARRISVILLE LINE.  CLOUDS WILL THIN BEHIND
THE RAIN BAND...WITH INCREASING SUN ACROSS NORTHERN PORTIONS OF THE
FORECAST AREA DURING THE AFTERNOON.  TEMPERATURES WILL STEADY OUT OR
FALL OFF DURING THE AFTERNOON...MUCH COOLER THAN TODAY WITH
TEMPERATURES DURING THE AFTERNOON IN THE UPPER 40S AND 50S EXPECTED
WITH A NORTHERLY BREEZE NOT HELPING MATTERS.  AS CLOUDS PUSH SOUTH
ALONG WITH THE SURFACE HIGH...OVERNIGHT LOW TEMPERATURES COME INTO
FOCUS IN COOLER POST-FRONTAL AIR MASS.  ONE IMPACT ON POTENTIAL LOW
TEMPERATURES WILL BE WHETHER WE DECOUPLE AND WINDS CAN SLACK OFF.
ONE ISSUE WILL BE LOCATION OF COLD FRONT...AND WITH LINGERING EXIT
REGION DYNAMICS ALONG THE BOUNDARY THE POSSIBILITY THAT A FRONTAL
WAVE SPINNING UP ALONG THE FRONT WILL SLOW THE BOUNDARY`S SOUTHWARD
PROGRESSION AND KEEP SOME GRADIENT IN PLACE ACROSS LOWER MICHIGAN
THROUGH THE NIGHT.  THIS MAY TEMPER LOW TEMPERATURES SUNDAY MORNING
AND WILL TREND AWAY FROM FROST POTENTIAL ACROSS NORTHERN LOWER FOR
NOW DUE TO THE UNCERTAINTY REGARDING WINDS.  WILL STILL MENTION
POSSIBILITY ABOVE THE BRIDGE WHERE IT IS MORE LIKELY WINDS WILL
SLACK OFF OVERNIGHT.

SUNDAY...SHAPING UP TO BE A NICE DAY SUNDAY THOUGH WILL BE ON THE
COOL SIDE OF NORMAL TO END THE MONTH OF MAY WITH HIGHS IN THE 50S
ACROSS EASTERN UPPER/NORTHEAST LOWER WHERE A CHILLY WIND OFF LAKE
HURON WON`T HELP...AND 60-65 ACROSS NORTHWEST LOWER (NORMAL HIGHS
FOR SUNDAY RANGE FROM 67-70).  COOL START TO THE NIGHT WILL RAISE
CONCERNS ABOUT LOW TEMPERATURES MONDAY MORNING...STILL SOME ISSUES
WITH WINDS ACROSS NORTHERN LOWER AND POSSIBILITY OF SOME MID CLOUDS
DEVELOPING ACROSS EASTERN UPPER AS SHORT WAVE TROUGHING TAKES SHAPE
OVER LAKE SUPERIOR/UPPER MICHIGAN.  IF WINDS CAN DECOUPLE THEN CAN
SEE SOME AREAS DROPPING INTO THE 20S OVERNIGHT...BUT EVEN NEAR
FREEZING LOWS A REASONABLE POSSIBILITY.

MONDAY...SURFACE HIGH PRESSURE RIDGE WILL STILL HOLD FAST ACROSS THE
UPPER GREAT LAKES EXTENDING SOUTHWEST FROM QUEBEC.  DEVELOPING SHORT
WAVE TROUGH MAY BRING SOME MID CLOUDS AND FILTERED SUNSHINE TO THE
AREA.  MORE WIDESPREAD HIGHS IN THE 60S EXPECTED MONDAY AFTERNOON.

&&

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 407 PM EDT FRI MAY 29 2015

HIGH IMPACT WEATHER POTENTIAL: NONE TO SPEAK OF...POSSIBLY SOME
FROST?

THE EXTENDED PERIOD LOOKS EXTREMELY QUIET. THE EURO SHOWS OUR PERIOD
BEGINNING WITH THE PASSING OF A RATHER UNIMPRESSIVE SHORTWAVE MONDAY
NIGHT/TUESDAY MORNING...BUT WITH NO MOISTURE (OR ANY OTHER SUPPORT)
TO WORK WITH...SHOULD GO BY UNNOTICED. A BROAD AREA OF HIGH PRESSURE
IS THE DOMINANT WEATHER FEATURE THROUGHOUT THE HEART OF NEXT
WEEK...PROVIDING DRY CONDITIONS INTO THURSDAY...THATS WHEN OUR RIDGE
BEGINS TO BREAK DOWN. MODEL TRENDS HAVE BEEN AMBITIOUS TO BRING POPS
IN LATELY...ALL TO RESULT IN NOT. GUT FEELING IS...MORE CONFIDENT
THAT WE WONT SEE ANY ACTUAL RAINFALL UNTIL LATER ON FRIDAY...BUT
WILL KEEP CHANCE POPS IN FOR THURSDAY TO BLEND WITH OTHERS...AS THIS
IS STILL A GOOD WAYS OFF.

TEMPERATURES WILL BEGIN TO STEADILY CLIMB EACH DAY NEXT
WEEK...THOUGH WITH A VERY SHARP DIURNAL DIP ESPECIALLY EARLY IN THE
PERIOD...A TESTAMENT TO THE DRY SUBSIDENCE IN PLACE. DAYTIME HIGHS
WILL BE NEAR CLIMO ON TUESDAY...WARMING TO WELL ABOVE NORMAL HIGHS
BY THE END OF THE PERIOD. OVERNIGHT LOWS AFTER TUESDAY WILL BE RIGHT
IN THE WHEELHOUSE FOR EARLY JUNE AS WELL.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 902 PM EDT FRI MAY 29 2015

...MVFR TO IFR CONDITIONS LIKELY OVERNIGHT INTO SATURDAY
MORNING...

SURFACE COLD FRONT STRETCHES FROM SW ONTARIO DOWN THROUGH CENTRAL
UPPER MICHIGAN AND INTO EASTERN WISCONSIN. AHEAD OF THE
FRONT...SEVERAL POCKETS OF SHOWERS AND A FEW THUNDERSTORMS
CONTINUE TO RUN UP THROUGH LOWER MICHIGAN WITHIN THE FAIRLY WARM
AND HUMID AIRMASS ACROSS THE REGION. BUT OVERALL VFR CONDITIONS
PREVAIL AND WILL CONTINUE TO PREVAIL THROUGH THE REST OF THE
EVENING...SAVE FOR SOME BRIEF VSBY REDUCTIONS IN HEAVIER SHOWERS.

COLD FRONT PUSHES DOWN THROUGH NRN LOWER MICHIGAN OVERNIGHT
(BETWEEN 06Z AND 12Z). WEDGE OF MUCH COOLER LOW LEVEL AIR
UNDERCUTTING THE WARMER/HUMID AIRMASS WILL LEAD TO THE DEVELOPMENT
OF IFR CIGS DURING THE OVERNIGHT PERIOD AND PERHAPS SOME FOG.
MEANWHILE...STRONG UPPER JET STREAK RIDES UP THROUGH THE NRN LAKES
AND WILL LEAD TO THE DEVELOPMENT OF A CORRIDOR OF WIDESPREAD
RAINFALL BEHIND THE FRONT THAT WILL IMPACT NRN LOWER MICHIGAN
LATER OVERNIGHT THROUGH SATURDAY MORNING.

WINDS INCREASE OUT OF THE NW ON SATURDAY AND USHER IN COOLER/MUCH
DRIER AIR INTO THE REGION. THIS WILL BRING QUICK IMPROVEMENT ON
SATURDAY WITH ALL TERMINAL SITES RETURNING TO VFR CONDITIONS BY
MIDDAY. SOME GUSTINESS ANTICIPATED SATURDAY WITH GUSTS INTO THE
LOWER 20 KNOT RANGE THROUGH THE AFTERNOON.


&&

.MARINE...
ISSUED AT 407 PM EDT FRI MAY 29 2015

STRENGTHENING COLD FRONT CROSSES THE AREA TONIGHT...
BRINGING SHOWERS AND STORMS ALONG WITH IT. INITIAL SOUTH WINDS WILL
RAPIDLY VEER NORTHWEST IN THE PROCESS...BECOMING INCREASINGLY GUSTY
BY MORNING. NOT EXPECTING ANY SCA CONDITIONS TONIGHT...ALTHOUGH
WINDS COULD BE QUITE GUSTY IN THE VICINITY OF THUNDERSTORMS.

NORTHWEST TO NORTH WINDS CONTINUE TO INCREASE IN SPEED
SATURDAY...WITH WINDS BECOMING NORTHEAST SATURDAY NIGHT. STRONG
PRESSURE GRADIENT AND INCREASING OVER-WATER INSTABILITY WILL LIKELY
SUPPORT SCA PRODUCING WINDS AND WAVES OVER MUCH OF THE NEARSHORE
WATERS.


&&

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

$$

UPDATE...ADAM
NEAR TERM...MSB
SHORT TERM...JPB
LONG TERM...KAB
AVIATION...ADAM
MARINE...MSB


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