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000
FXUS63 KAPX 250438
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1138 PM EST SAT JAN 24 2015

.UPDATE...
ISSUED AT 1035 PM EST SAT JAN 24 2015

03Z SFC ANALYSIS REVEALING COLD FRONT THAT PASSED THROUGH NRN
LOWER MICHIGAN EARLIER IN THE DAY...NOW SLIPPING DOWN INTO SRN
LOWER...ROUGHLY STRETCHING FROM NORTH OF FLINT OVER TO MUSKEGON.
NORTHERLY COLD/DRY AIR ADVECTION NOW UNDERWAY ACROSS NRN MICHIGAN
COURTESY OF STRONG CANADIAN HIGH PRESSURE BUILDING DOWN THROUGH
ONTARIO. DRY AIR ALREADY MAKING IT/S PRESENCE KNOWN WITH
PRONOUNCED CLEARING ALREADY ACROSS EASTERN UPPER MICHIGAN AND DOWN
INTO THE TIP OF THE MITT.

REST OF TONIGHT...HIGH PRESSURE CONTINUES TO BUILD DOWN THROUGH
WESTERN ONTARIO AND DOWN ACROSS THE NRN LAKES...PUSHING -10C TO
-15C H8 AIR INTO THE REGION BY MORNING. BUT AS MENTIONED
ABOVE...INCOMING AIRMASS IS VERY DRY WITH LAYER PWAT VALUES
DROPPING BELOW 0.10 INCH. COMBINED WITH OVERALL NORTH TO NNE LOW
LEVEL FLOW TRAJECTORIES (LARGELY UNFAVORABLE FOR LES)...LAKE
EFFECT POSSIBILITIES FOR THIS CWA WILL BE MINIMAL. ONLY EXCEPTION
MIGHT BE PARTS OF NE LOWER MICHIGAN WHERE CLOUDS AND SOME LIGHT
SNOW SHOWERS MAY LINGER (ALREADY SEEING SOME HINTS OF NUISANCE
LAKE EFFECT ON RADAR DATA). GOING FORECAST ALREADY HAD THIS IDEA
WITH JUST SOME MINOR TWEAKING ON MY PART.

ELSEWHERE...PRETTY GOOD SHOT AT THINNING CLOUDS IF NOT FLAT OUT
CLEARING SKIES AS THAT COLD/DRY AIR WEDGES DOWN THROUGH THE
REGION. WINDS WILL CURTAIL SUBSTANTIAL RADIATIONAL COOLING...BUT
TEMPS WILL FALL INTO THE SINGLE DIGITS TO THE TEENS (BELOW ZERO IN
EASTERN UPPER) JUST BY VIRTUE OF COLD ADVECTION.

UPDATE ISSUED AT 711 PM EST SAT JAN 24 2015

PER SATELLITE IMAGERY...ONE MORE POCKET OF FORCING/ENHANCEMENT IS
NOW SLIDING THROUGH LOWER MICHIGAN THIS EVENING...BRINGING SOME
ADDITIONAL LIGHT SNOWS TO THE SW/SRN COUNTIES. NOT VERY
SUBSTANTIAL...BUT VARIOUS OBS (TVC/FKS/CAD) HAVE BEEN REPORTING
VIS REDUCTIONS OF 2SM OR LESS OVER THE LAST HOUR OR SO.
THUS...HAVE INTRODUCED A PERIOD OF HIGHER POPS THROUGH THAT
CORRIDOR FOR THE NEXT FEW HOURS UNTIL THAT ENHANCEMENT MOVES ON TO
THE E/SE. OTHERWISE...WINDS ARE SWITCHING ABRUPTLY NNW ACROSS THE
CWA AND GUSTY USHERING IN COLDER BUT DRIER AIR INTO THE REGION.
TEMPS WILL FALL INTO THE SINGLE DIGITS TO THE TEENS THROUGH THE
NIGHT...BUT EXPECT SOME CLEARING TO TAKE SHAPE AS WELL.

&&

.NEAR TERM...(THIS EVENING THROUGH TONIGHT)
ISSUED AT 234 PM EST SAT JAN 24 2015

HIGH IMPACT WEATHER POTENTIAL: NONE.

PATTERN: BROAD NORTHWESTERLY FLOW ALOFT CONTINUES THIS AFTERNOON
BETWEEN SUBSTANTIAL RIDGING ALONG THE WEST COAST OF NOAM...AND
DEEPENING TROUGH RESPONSIBLE FOR LOW PRESSURE ALONG THE EAST COAST.
A SHORTWAVE EMBEDDED WITHIN THIS FLOW IS EVIDENT IN EARLY AFTERNOON
WATER VAPOR IMAGERY OVER LAKE SUPERIOR PRETTY MUCH ALIGNED WITH A
SURFACE COLD FRONT THAT IS SWEEPING SOUTH AND EAST THROUGH NORTHERN
MICHIGAN AS OF THIS WRITING.  DARKENING ON THE AFOREMENTIONED WV
IMAGERY BEHIND THIS WAVE CORRESPONDS TO DEEP-LAYER DRY AIRMASS THAT
HAS RESULTED IN FULL CLEARING NORTH OF THE WESTERN GREAT LAKES AS
SEEN IN VISIBLE SATELLITE IMAGERY. THIS DRY AIR WILL PUSH SOUTH INTO
OUR AREA OVERNIGHT BRINGING AND END TO THE LIGHT MIXED PRECIPITATION
WE HAVE BEEN DEALING WITH TODAY AND REINTRODUCING ARCTIC AIR.

THE DETAILS...

THROUGH THIS EVENING: SURFACE WIND SHIFT LINE IS A LITTLE AHEAD OF
THE SIGNIFICANTLY COOLER AIR...AND WILL CONTINUE TO PUSH SOUTH AND
EAST THROUGH THE FORECAST AREA.  DRYING WILL TRY TO WORK INTO
EASTERN UPPER THROUGH 7PM...WITH CONTINUED LIGHT SHSN /PERHAPS EVEN
A FEW RAIN DROPS NEAR THE LAKES/ IN THE DEEPER MOISTURE OVER
NORTHERN LOWER. TEMPS WILL QUICKLY FALL INTO THE TEENS THROUGH 7PM
OVER EASTERN UPPER...AND INTO THE 20S OVER NORTHERN LOWER.

TONIGHT: DRYING FROM THE NORTH IS NEVER CLEAR CUT AS THE LAKES WILL
BE COAXED INTO /LIMITED/ ACTION BY T8S FALLING THROUGH THE LOWER
MINUS TEENS OVERNIGHT.  AIRMASS ALOFT IS VERY...VERY DRY /850-700 RH
NEAR 10 PERCENT/...SO ANY RESPONSE WILL BE SHALLOW AND LIMITED.
WITH FLOW TRAJECTORIES GAINING A NORTHEASTERLY COMPONENT AFTER
MIDNIGHT EXPECT THAT MOST OF THE LAKE MICHIGAN CLOUDINESS WILL
REMAIN OFFSHORE WITH PRIMARY CONCERNS TURNING TO NORTHEAST LOWER.
DESPITE VERY SHALLOW RESPONSE EXPECTED...ANY LAKE INDUCED LIFT DOES
LOOK TO RESIDE IN THE DENDRITIC GROWTH ZONE...SO I DO THINK WE/LL
SQUEEZE OUT A FEW FLURRIES AND WILL CONTINUE MENTION OF THEM ALONG
THE COAST.  TO THE WEST OF THIS...GRADUAL CLEARING FROM NORTH TO
SOUTH AS VERY DRY AIR BLEEDS IN FROM THE NORTH.

TEMPERATURES: WILL FALL RAPIDLY OVERNIGHT WITH PUSH OF ARCTIC AIR.
BACKWARD TRAJECTORIES INDICATE FAR NORTHERN ONTARIO WILL BE THE
SOURCE FOR THE AIR ARRIVING OVER THE REGION TOWARDS DAYBREAK WITH
LOWS IN THIS AREA THIS MORNING FALLING ON EITHER SIDE OF ZERO.  THE
TRAJECTORIES FAVOR ONLY SLIGHT MODERATION TO THIS AIRMASS AS IT
ARRIVES...WITH PRIMARY COMPLICATING FACTOR BEING CLOUDS.  EXPECT
LOWS TO FALL TO NEAR OR A LITTLE BELOW ZERO FOR THE EASTERN
UP...WITH SINGLE DIGITS INTO THE LOWER TEENS FOR NORTHERN
LOWER...WARMEST NEAR THE LAKES.

&&

.SHORT TERM...(SUNDAY THROUGH TUESDAY)
ISSUED AT 234 PM EST SAT JAN 24 2015

HIGH IMPACT WEATHER POTENTIAL: MINIMAL

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: THE REMARKABLY UNEVENTFUL
WEATHER LOOKS TO CONTINUE...WITH THE LARGE SCALE BACKGROUND PATTERN
CHANGING LITTLE FROM THAT WHICH HAS BROUGHT US WEEKS OF VERY QUIET
CONDITIONS. NO DOUBT THE PATTERN IS AN AMPLIFIED ONE...AND EERILY
SIMILAR TO WHAT OCCURRED LAST WINTER...WITH DEEP EAST NAMERICA
TROUGHING DOWNSTREAM FROM JUST AS IMPRESSIVE WESTERN RIDGE AXIS.
THERMAL GRADIENT AND UPPER JET ENERGY ALL SUPPORT NEXT CLIPPER
SYSTEM CURRENTLY DIVING THROUGH SOUTHERN SASKATCHEWAN TO SAFELY PASS
WELL TO OUR WEST AND SOUTH TONIGHT THROUGH SUNDAY. SUBTLE AND
TEMPORARY READJUSTMENT TO LARGER PATTERN ALLOWS NEXT WAVE TO MAKE A
RUN AT OUR AREA TO KICK OFF NEXT WORK WEEK. EXCEEDINGLY DRY LOW
LEVEL ENVIRONMENT WILL HAVE PLENTY TO SAY ON JUST HOW LITTLE SNOW
FALLS WITH THIS SYSTEM.

PRIMARY FORECAST CHALLENGES/CONCERNS: TEMPERATURE TRENDS AND
ADDRESSING LIGHT SNOW POTENTIAL WITH THAT EARLY WORK WEEK CLIPPER
SYSTEM.

DETAILS: AS MENTIONED EARLIER...NOW UNANIMOUS SUPPORT ALL INFLUENCE
ASSOCIATED WITH NEXT CLIPPER SYSTEM WILL PASS WELL OFF TO OUR SOUTH
SUNDAY...PRIMARILY AFFECTING THE OHIO VALLEY. ELONGATED CANADIAN HIGH
PRESSURE BUILDS SOUTH ACROSS THE AREA THROUGH THE DAY AND OVERNIGHT
SUNDAY. ASSOCIATED DRYING IS IMPRESSIVE...ALTHOUGH WILL NEED TO
WATCH EXTREMELY LOW LEVEL LAKE HURON MOISTURE CONTRIBUTION IN LIGHT
NORTHEAST TO EAST FLOW REGIME. WITH SUB 9H INVERSION LEVEL
TEMPERATURES COOLING THROUGH THE DGZ...EVEN SOME HINTS OF POSSIBLE
LAKE INDUCED FLURRIES. NOT A BIG DEAL FOR SURE...AND SIMPLY GOING TO
SPLIT THE DIFFERENCE ALLOWING CLOUDS TO HANG ON LONGEST NORTHEAST
LOWER...WHILE SHOWING SUBSTANTIALLY CLEARING ACROSS NORTHWEST LOWER
AND EASTERN UPPER MICHIGAN. TEMPERATURES WILL BE SUBSTANTIALLY
COLDER...WITH INVERSION LEVEL READINGS SUGGESTING HIGHS REMAINING
MOSTLY IN THE TEENS. WINDS WILL BE LIGHT...KEEPING WIND CHILL
READINGS JUST A TOUCH COOLER THAN ACTUAL TEMPERATURES. LIGHT
WINDS/MAINLY CLEAR SKIES SETS THE STAGE FOR A RATHER COLD SUNDAY
NIGHT. HAVE NOT DEVIATED MUCH FROM INHERITED LOWS IN THE SINGLE
DIGITS BELOW ZERO ACROSS THE TRADITIONAL ICE BOX LOCATIONS...WHICH
ARE AT LEAST A FEW DEGREES COOLER THAN MOST STATISTICAL GUIDANCE.

NEXT CLIPPER SYSTEM SET TO ARRIVE LATER MONDAY/MONDAY NIGHT
ESSENTIALLY RUNS INTO A BRICK WALL AS LOW PRESSURE RAPIDLY
INTENSIFIES OFF THE EASTERN SEABOARD. LOW LEVEL DRY AIR FEED NORTH
OF THIS EASTERN SYSTEM SPILLS INTO NORTHERN MICHIGAN. ECMWF/GEM MOST
AGGRESSIVE IN THIS REGARD...REALLY STRUGGLING TO ALLOW THE LOW
LEVELS TO MOISTEN VIA TOP-DOWN SATURATION. GFS/NAM ALLOW FALLING
SNOW FROM MID LEVEL CLOUD DECK TO GRADUALLY COMPLETE THE SATURATION
PROCESS...EVEN SUGGESTING SOME LIGHT SNOW ACCUMULATION (LARGELY
UNDER AN INCH) BY TUESDAY MORNING. GIVEN CURRENT TRENDS FOR A
SUBSTANTIAL EAST COAST SYSTEM...KINDA SIDING WITH THE LESS
AGGRESSIVE MOISTENING SOLUTIONS. CHANCE POPS WILL SUFFICE FOR
NOW...HIGHEST WEST. REALLY...EITHER WAY...NOT GOING TO BE A BIG
DEAL. HIGH PRESSURE REINSERTS ITSELF TUESDAY...ENDING ANY OF THAT
LIGHT SNOW NONSENSE.

&&

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 234 PM EST SAT JAN 24 2015

LOOKING LIKE AN INCREASED LIKELIHOOD FOR SOME ACCUMULATING SNOW AS A
CLIPPER SYSTEM MOVES INTO THE REGION WEDNESDAY NIGHT THROUGH
THURSDAY. MAJOR AMOUNTS NOT EXPECTED...BUT COULD SEE A COUPLE INCHES
OF ACCUMULATION FOR THE FIRST TIME IN A WHILE. COLD AIR FILTERING IN
BEHIND THE DEPARTING CLIPPER WILL BRING SOME LAKE EFFECT SNOWS TO
TYPICAL SNOW BELT AREAS FRIDAY AND SATURDAY. AFTER A MILD START WITH
TEMPERATURES IN THE MID 20S TO LOW 30S...HIGHS WILL DIP INTO THE
TEENS FOR FRI AND SAT. WEEKEND LOWS WILL BE IN THE SINGLE DIGITS
ABOVE AND BELOW ZERO.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1138 PM EST SAT JAN 24 2015

...SLOWLY BECOMING VFR...

MVFR CIGS ACROSS NRN LOWER MICHIGAN WILL GIVE WAY TO VFR CONDITIONS
AT THE TERMINAL SITES DURING THE REST OF THE OVERNIGHT HOURS AND
PERSISTING THROUGH SUNDAY...AS HIGH PRESSURE/DRY AIR BUILDS INTO
NRN MICHIGAN. APN MAY BE THE EXCEPTION...WHERE N/NNE FLOW OFF LAKE
HURON MAY KEEP LAKE CLOUDS AND PERHAPS EVEN SOME LIGHT SNOW
SHOWERS AROUND INTO SUNDAY.

WINDS...N/NNE TONIGHT THROUGH SUNDAY. A LITTLE GUSTINESS OUT THERE
THROUGH THE DAY SUNDAY...BECOMING CALM SUNDAY NIGHT.

&&

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

$$

UPDATE...ADAM
NEAR TERM...ARNOTT
SHORT TERM...MSB
LONG TERM...ALM
AVIATION...ADAM