Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 280513
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
113 AM EDT SAT MAR 28 2015

.UPDATE...
ISSUED AT 106 AM EDT SAT MAR 28 2015

TEMPS ON TRACK FOR NEAR RECORD COLD READINGS OVERNIGHT UNDER IDEAL
RADIATIONAL COOLING CONDITIONS. WILL ADJUST A FEW READINGS LOWER
BASED ON CURRENT OBSERVATIONS. EXPECT SEVERAL BELOW ZERO READINGS
BY SATURDAY MORNING...ESPECIALLY EASTERN UPPER AND AU SABLE VALLEY
IN NORTHERN LOWER.

UPDATE ISSUED AT 1027 PM EDT FRI MAR 27 2015

HIGH PRESSURE CONTINUES TO BUILD INTO MICHIGAN...AND WILL REMAIN
IN PLACE OVERNIGHT. UNDER CLEAR SKIES AND DIMINISHING WINDS...
TEMPS WILL PLUMMET INTO THE SINGLE DIGITS ABOVE AND BELOW ZERO.
STAY WARM!

&&

.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 344 PM EDT FRI MAR 27 2015

...MAINLY CLEAR AND VERY COLD...

ON THE LATEST SURFACE WEATHER MAP...TROUGHING IS MOVING OFF TO OUR
EAST WHILE 1028 MB HIGH PRESSURE CENTERED ACROSS NORTHERN LAKE
SUPERIOR IS BUILDING IN. SATELLITE IMAGERY SHOWED LINGERING LAKE
BANDING ALONG THE LAKE HURON AND LAKE MICHIGAN SHORELINES. APX RADAR
AND SURFACE OBSERVATIONS WERE NOT SHOWING ANY SNOW SHOWER ACTIVITY
ANY MORE. THE MAIN NEAR TERM FORECAST CONCERN REVOLVES AROUND HOW
COLD IT WILL GET TONIGHT.

SO WITH HIGH PRESSURE CONTINUING TO BUILD IN FROM THE NORTHWEST...IN
COMBINATION WITH DIMINISHING WINDS AND MAINLY CLEAR
SKIES...EXCELLENT RADIATIONAL COOLING CONDITIONS WILL DEVELOP
OVERNIGHT. THE ONLY FACTORS THAT APPEAR TO PREVENT THE TOTAL
CRATERING OF TEMPERATURES ARE THE SHORTER NIGHTS AND THE LACK OF AN
EXTENSIVE SNOWPACK EXCEPT FOR ACROSS THE HIGHER TERRAIN OF NORTHWEST
LOWER AND ACROSS MUCH OF EASTERN UPPER. TEMPERATURES WILL START OUT
ON THE CHILLY SIDE THIS EVENING SO WHEN WINDS EVENTUALLY DIMINISH IT
WILL NOT TAKE TOO MUCH TO GET VERY COLD LOWS. AT THIS POINT WILL GO
WITH SINGLE DIGITS BELOW ZERO WHERE ANY SNOW COVER REMAINS (PERHAPS
A FEW NEGATIVE TEENS AS WELL WITH SINGLE DIGITS ABOVE ZERO EXPECTED
FOR LOWS NEAR THE LAKE MICHIGAN AND LAKE HURON SHORELINES. THE ONLY
RECORD LOW THAT LOOKS TO BE CLOSE IS -4 IN HOUGHTON LAKE WHICH WAS
SET WAY BACK IN 1926.

&&

.SHORT TERM...(SATURDAY THROUGH MONDAY)
ISSUED AT 344 PM EDT FRI MAR 27 2015

...WINDY SUNDAY WITH A BURST OF SNOW FOR MOST...

HIGH IMPACT WEATHER POTENTIAL: STRONG WINDS AND ACCUMULATING SNOW
POTENTIAL SUNDAY.

PATTERN: PERSISTENT RIDGE-TROUGH PATTERN ACROSS NOAM WILL RELAX A
BIT THROUGH THE SHORT TERM FORECAST PERIOD AS PACIFIC SHORTWAVE
ENERGY FLATTENS THE WESTERN RIDGE AND RIDES EAST...IN THE END
PROVIDING REINFORCEMENT FOR THE EASTERN TROUGH.  SHORTWAVE RIDGING
AHEAD OF THIS FEATURE PROMISES A DRY SATURDAY...WITH THE WAVE ITSELF
BRINGING THE PRIMARY SENSIBLE WEATHER CONCERN FOR THE SECOND HALF OF
SUNDAY.

WEATHER:

SATURDAY-SATURDAY NIGHT...HIGH PRESSURE OVERHEAD FOR THE DAY ON
SATURDAY WITH COLD/DRY /PWATS SUB 0.1/ DIRECTLY OVERHEAD.  NORTH-
NORTHEAST LLEVEL FLOW TRAJECTORIES SPELL THE POTENTIAL FOR A FEW
LAKE INDUCED CLOUDS ALONG MAINLY THE LAKE HURON COAST IN THE
MORNING...BUT DRYNESS OF AIRMASS ALONG WITH WEAKENING/BACKING LLEVEL
FLOW SHOULD EVEN BRING AN END TO THESE...WITH SUNNY/MOSTLY SUNNY
CONDITIONS FOR ALL AREAS.  THE HIGH SETTLES SOUTH AND EAST OF THE
REGION SATURDAY NIGHT...ALLOWING FOR DEVELOPING RETURN FLOW AND THE
START OF TOP-DOWN SATURATION AHEAD OF THE NEXT NORTHERN STREAM
SHORTWAVE.  1000 MB GEOSTROPHIC WINDS RAMP UP RAPIDLY BY LATE
EVENING...WITH FULL COUPLING EXPECTED FOR THE MAJORITY OF THE
OVERNIGHT...AS HIGH CLOUDS THICKEN.  ALL IN ALL...A PARTLY CLOUDY
AND INCREASINGLY BREEZY NIGHT IS EXPECTED.

SUNDAY-SUNDAY NIGHT:  STRONG /~990 MB/ LOW PRESSURE SYSTEM PASSES
NORTH OF THE GREAT LAKES WITH GOOD MODEL AGREEMENT ON THE TRACK OF
THIS FEATURE.  THIS LOW WILL COAX AN IMPRESSIVE SOUTHWESTERLY LLEVEL
JET RESPONSE /50KTS AT H9 AND 60KTS AT H8/ THAT WILL TRANSPORT PWATS
OF 0.6" /TOP TENTH PERCENTILE FOR THIS TIME OF YEAR/ INTO MICHIGAN
AHEAD OF AN APPROACHING COLD FRONT. FORCING FOR ASCENT IS MODEST
WITH FAST MOVING...DOUBLE-BARRELED SHORTWAVE AT H5 PROVIDING A
MODEST BULLSEYE OF QG FORCING WITH WEAK SUPPORT AT JET STREAM LEVEL
/85KT JET STREAK DROPPING THROUGH THE REGION/.  WITH DECENT
MOISTURE/FORCING...FULLY EXPECT A BAND OF PRECIPITATION THAT PUSHES
THROUGH THE REGION...BEGINNING OVER CHIP/MACK NEAR OR JUST
AFTERNOON...AND PROGRESSING THROUGH THE REMAINDER OF THE CWA DURING
THE AFTERNOON AND EARLY EVENING.  ANTECEDENT PROFILES ARE COOL/DRY
WITH WET-BULB TEMPERATURES NO MORE THAN ABOUT +1C THROUGH THE
COLUMN.  EXPECT THAT FOR MOST LOCATIONS...AFTER PERHAPS A FEW
INITIAL RAIN DROPS...THAT MOST OF WHAT FALLS WILL COME AS SNOW AS
EVAPORATIONAL/MELTING INDUCED COOLING BRINGS THE COLUMN BELOW
FREEZING. EXCEPTION TO THIS WILL BE WEST OF US-131 AND ALONG THE
LAKE HURON COAST SOUTH OF APN WHERE BOUNDARY LAYER TEMPERATURES WILL
BE MARGINAL FOR SOME MIX WITH RAIN.  THIS SYSTEM WILL BE A QUICK
HITTER...WITH NO MORE THAN A 3-5 HOUR WINDOW OF STEADY
PRECIPITATION.  THIS...AND WANING DEEP MOISTURE AS THE MOISTURE
PLUME PEELS EAST SHOULD LIMIT QPF TO 0.1-0.3".  SNOW RATIOS WON/T BE
TERRIFIC /PARTICULARLY NEAR THE LAKE MICHIGAN-HURON COASTS/...BUT A
QUICK 1-3 INCHES OF SNOW LOOKS POSSIBLE...ESP OVER EASTERN UPPER AND
INTERIOR NORTHERN LOWER.  EVENING TRAVEL SUNDAY WILL LIKELY BE SLICK
FOR A TIME.  THE OTHER BIG STORY ON SATURDAY WILL BE THE WINDS.  AS
MENTIONED ABOVE...H9 WINDS OF 50KTS DEFINITELY GET YOUR
ATTENTION...AND IN THE PRE-FRONTAL ENVIRONMENT...SURFACE BASED LAPSE
RATES WILL BE SUFFICIENT FOR DECENT MOMENTUM TRANSPORT.  THIS IS
PRETTY MUCH ALL GRADIENT-DRIVEN WITH LITTLE ISALLOBARIC
ASSISTANCE...BUT IS IMPRESSIVE NONETHELESS.  SEE NO REASON WHY WE
WON/T BE ABLE TO TRANSPORT SOME 35-40KT GUSTS TO THE SURFACE WITH
SUSTAINED WINDS 15 TO 25 MPH. GIVEN THAT THIS BRUSHES OUR ADVISORY
CRITERIA...WILL BEEF UP MENTION OF THE WINDS IN THE AFTERNOON
HAZARDOUS WEATHER OUTLOOK. ONCE THE SNOW BEGINS...THE LLEVLS
ACTUALLY STABILIZE SOME...SO...WHILE IT WILL REMAIN BREEZY INTO THE
EVENING...EXPECT WINDS MORE IN THE 10G20-25 MPH RANGE WHILE IT/S
SNOWING.  MESSY NONETHELESS.

COLD ADVECTION BEHIND THE DEPARTING FRONT SUNDAY NIGHT WILL BE
MEAGER TO ALMOST NON-EXISTENT WITH T8S DROPPING 1-2C OVERNIGHT...BUT
REMAINING IN THE NEGATIVE SINGLE DIGITS.  THESE TEMPERATURES DO NOT
SUPPORT MUCH POST-FRONTAL LAKE ASSISTANCE FOR ANY ADDITIONAL SNOWS
OVERNIGHT...BUT ONGOING CYCLONIC FLOW /AND UNSTABLE PROFILES/ IN THE
PRESENCE OF LINGERING H8-7 MOISTURE SHOULD SQUEEZE OUT ADDITIONAL
SHSN THROUGH THE NIGHT...WITH ONLY MINOR ADDITIONAL ACCUMULATIONS.
WINDS WILL REMAIN BLUSTERY OVERNIGHT...BUT WITH ONLY MINOR COLD
ADVECTION...WINDS WILL BE LIGHTER THAN DURING THE DAY SUNDAY
/15G25MPH/.  QUIETER WEATHER SETTLES IN FOR MONDAY AS WEAK SURFACE
HIGH PRESSURE AXIS SETTLES INTO THE GREAT LAKES REGION.  LLEVEL
MOISTURE CONTINUES TO THIN...BUT COULD SEE A FEW FLURRIES/SPRINKLES
ESPECIALLY DURING THE MORNING HOURS.

TEMPERATURES: T9S AROUND -7C YIELD HIGHS AROUND 30F WITH MIXING
LIMITED ABOVE THIS LEVEL GIVEN NEARBY SURFACE HIGH.  LOW
TEMPERATURES A BIT TRICKY SATURDAY NIGHT WITH INCREASING LLEVEL
GRADIENT KEEPING CONDITIONS COUPLED FOR MUCH OF THE NIGHT...BUT AS
IS ALL TO COMMON AROUND HERE...COULD SEE A FEW HOURS OF CALM WINDS
DURING THE EVENING.  THIS SHOULD ALLOW LOWS TO FALL BACK INTO THE
TEENS /PERHAPS EVEN UPPER SINGLE DIGITS FOR A FEW OF THE COLDER
SPOTS IN NE LOWER/ BEFORE RISING BACK THROUGH THE TEENS OVERNIGHT.
SUNDAY/S TEMPERATURES ALSO LOOK TRICKY WITH ANY "WARMTH" ALOFT
COINCIDING WITH PRECIPITATION...SO EXPECT HIGHS IN THE MID/UPPER 30S
AS T9S CLIMB TOWARDS 0C...WITH TEMPS FALLING BACK TO 29-33 AFTER
PRECIPITATION ONSET.  CLOUDS...WIND AND ONLY WEAK COLD ADVECTION
WILL ALLOW LOWS TO REMAIN ELEVATED SUNDAY NIGHT...UPPER 20S TO LOWER
30S.  BETTER MIXING AND T8S AROUND -9C ON MONDAY SHOULD ALLOW HIGHS
BACK TO AROUND TO 40F MARK.

&&

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 344 PM EDT FRI MAR 27 2015

PATTERN SYNOPSIS/FORECAST: AMPLIFIED RIDGE WEST/TROUGH EAST (+PNA)
PATTERN ACROSS NORTH AMERICA WILL BECOME A LITTLE FLATTER IN THE
MEAN THIS WEEKEND AS SHORT WAVE ENERGY OVER THE EASTERN PACIFIC
FLATTENS THE WESTERN RIDGE AND ROLLS ACROSS THE MIDWEST AND INTO THE
GREAT LAKES FOR THE LATTER HALF OF THE WEEKEND.  THIS MORE PACIFIC-
DOMINANT PATTERN LOOKS TO HOLD THROUGH MUCH OF NEXT WEEK...PERHAPS
TRENDING MORE UNSETTLED TOWARD NEXT WEEKEND.

A TREND TOWARD HEIGHT RISES DURING MIDWEEK FOR THE GREAT LAKES WILL
BE FOLLOWED BY PACIFIC SHORT WAVE ENERGY THOUGH EVOLUTION OF THIS
IDEA (TIMING/NUMBER OF SHORT WAVE TROUGHS INVOLVED) IS STILL VERY
MUCH IN FLUX.  ONE OF THE UPSHOTS OF THESE POTENTIAL FORECAST
DIFFERENCES IS WHETHER ANOTHER ROUND OF POLAR AIR IS ALLOWED TO
SWEEP INTO THE REGION BY NEXT WEEKEND (ADVERTISED BY THE GFS)...NOT
A TERRIBLE IDEA AS AMPLIFIED MJO SWINGS AROUND INTO THE COLD PHASES 2
AND 3 ALONG WITH SUPPORT FROM CPC ANALOGS.

FORECAST TRENDS: LITTLE CLIPPER WAVE SLIDES THROUGH MONDAY NIGHT
INTO TUESDAY WHICH WILL BRING A CHANCE OF SNOW TO MOST IF NOT ALL OF
THE AREA DEPENDING ON TRACK.  WILL TREND THINGS DRIER FOR WEDNESDAY
(AND WARMER) BEFORE RAMPING PRECIP CHANCES AGAIN HEADING INTO
THURSDAY.  IF THE TREND TOWARD A MORE ROBUST SHORT WAVE TROUGH
FORECAST BY THE GFS IS CORRECT...PERHAPS SOME THREAT FOR THUNDER ON
THURSDAY AS WELL. WILL COOL THINGS DOWN FOR FRIDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 106 AM EDT SAT MAR 28 2015

VFR THROUGH THIS TAF PERIOD. CLEAR SKIES AND WINDS LESS THAN
10KTS. LAKE BREEZES POSSIBLE THIS AFTERNOON ALONG LAKE MICHIGAN
POTENTIALLY AFFECTING TVC/MBL. LLWS DEVELOPING AFTER 06Z /OUTSIDE
OF CURRENT TAF PERIOD/ AT PLN-TVC-MBL AND WILL BE INCLUDED IN THE
12Z TAF ISSUANCE.

&&

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

$$

UPDATE...KEYSOR
NEAR TERM...SULLIVAN
SHORT TERM...ARNOTT
LONG TERM...JPB
AVIATION...KEYSOR


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