Au Sable, MI, United States
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Lat: 44.41N | Lon: 83.34W |
Wx Zone: MIZ036 |
ICAO Used: | County: Iosco | Forecast Office: KAPX | FIPS: 026069
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Au Sable, MI Area Forecast Discussion:
000
FXUS63 KAPX 081103
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
603 AM EST WED FEB 8 2012
.SYNOPSIS.../ISSUED AT 335 AM/
A LARGE AREA OF HIGH PRESSURE ACROSS THE NATION'S MIDSECTION EXTENDS
EAST ACROSS THE GREAT LAKES REGION. THIS WILL KEEP THE WEATHER DRY
ACROSS NORTHERN MICHIGAN TODAY THROUGH TONIGHT. THERE IS A COLD
FRONT POISED TO THE NORTH OF THE REGION ACROSS NORTHERN CANADA.
THIS FRONT IS SET TO BRING A SURGE OF COLD ARCTIC AIR INTO MICHIGAN
ON FRIDAY.
JPB
&&
.SHORT TERM.../ISSUED AT 335 AM/...TODAY
QUITE THE COLD START TO THE EARLY MORNING IN SPOTS...MUCH MORE IN
LINE WITH NORMAL FEBRUARY WX ACRS THE REGION...THANKS TO SPRAWLING
STRONG (1039MB) SURFACE RIDGING EXTENDING FROM THE NORTHERN PLAINS
THROUGH THE GREAT LAKES. THIS FEATURE WILL REMAIN IN CONTROL OF
OUR LOCAL WX HEADING THROUGH THE DAY TODAY...WITH LITTLE IN THE
WAY OF FCST CONCERNS...SAVE FOR SMALL POTENTIAL FOR SOME PESKY
STRATOCU AND JUST HOW WARM TEMPS WILL GET. EARLY MORNING SATELLITE
OBS SHOW A PLETHORA OF CLEAR SKIES ALL THROUGHOUT NORTHERN
MICHIGAN...WITH ONLY SOME THIN CIRRUS DRIFTING OVERHEAD. REMNANTS
OF EARLIER STRATOCU DECK ACRS EASTERN UPPER NOW EXITING STAGE
RIGHT...AS LOW LEVEL FLOW IS SLOWLY BACKING MORE WESTERLY IN
RESPONSE TO SURFACE RIDGE SETTLING SOUTHWARD INTO THE CENTRAL
PLAINS. BONE DRY AIRMASS (PWATS A MEASLY 0.09 INCHES PER 00Z APX
RAOB) HAS PREVENTED ANY REDEVELOPMENT OF LAKE MICHIGAN STRATOCU
DESPITE SAID BACKING FLOW...THOUGH IT IS CURIOUS TO SEE A COUPLE
OBS (CVX/FKS FOR INSTANCE) SHOWING THE OCCASIONAL SCT/BKN 2.5KFT
DECK AT TIMES...HINTING THAT LAKE STRATOCU IS DESPERATELY CLINGING
TO SOME ATTEMPT TO DEVELOP OFF THAT LAKE.
HEADING THRU THE DAY TODAY...AFOREMENTIONED LOW LEVEL RIDGE AXIS
OVERHEAD THIS MORNING WILL GRADUALLY SHIFT THROUGH THE LOWER GREAT
LAKES THIS AFTN...AS WEAK SHORTWAVE RIDGING GLIDES IN AT THE MID
LEVELS. LENGTHENING WESTERLY TRAJECTORIES WILL HELP DRAG IN A
GRADUALLY WARMER AIRMASS...THOUGH WITH SAID TRAJECTORIES ALSO
SUGGESTING OUR AIRMASS WILL REMAIN SUBSTANTIALLY DRY THRU THE DAY
(PWATS NO BETTER THAN 0.15 INCHES). THUS...CONTINUE TO BELIEVE THAT
ANY LAKE STRATOCU WILL HAVE A HARD TIME DEVELOPING INLAND...WITH ANY
STRAGGLERS THAT DO PERHAPS MANAGE TO DEVELOP RAPIDLY MIXING OUT JUST
AFTER SUNRISE. THUS...WILL CONTINUE WITH A SUNNY FCST JUST ABOUT ALL
SPOTS (MAYBE A BIT OF STRATOCU CLIPPING FAR NORTHERN CHIPPEWA
COUNTY)...WITH HIGHS REBOUNDING BACK THROUGH THE LOWER 30S IN MANY
AREAS.
LAWRENCE
&&
.LONG TERM.../ISSUED AT 335 AM/...TONIGHT AND BEYOND
BENIGN WX CONTINUES TONIGHT AND INTO THE DAY ON THURSDAY...WITH MAIN
FCST ISSUES DURING THIS TIME LIMITED TO SMALL POTENTIAL FOR SOME
PESKY STRATUS DEVELOPMENT LATE TONIGHT. BIGGER ISSUES ENTER THE FCST
THU NIGHT INTO FRI NIGHT AS AN ARCTIC COLD FRONT CROSSES THE
REGION...BRIEFLY USHERING IN SOME OF THE COLDEST AIR WE'VE SEEN SO
FAR THIS WINTER. IN THE MEANTIME...LOW LEVEL RIDGING WILL HANG ON
INTO TONIGHT AND MUCH OF THU...WITH FURTHER BACKING LOW LEVEL FLOW
HELPING TRANSPORT INCREASINGLY WARMER AIR BACK INTO THE REGION.
PATTERN TONIGHT CONTINUES TO HAVE SOME HINTS OF POSSIBLE STRATUS
DEVELOPMENT...WITH GOOD RESIDENCE TIME OF WESTERLY FLOW OVER LAKE
MICHIGAN BY THAT POINT (BETTER TIME TO INCREASE MOISTURE FLUX OFF
THE LAKE DESPITE WANING OVERLAKE INSTABILITY). SAID FLOW REGIME WILL
INCREASINGLY INTERACT WITH STRENGTHENING INVERSION AND UPSLOPE FLOW
INTO THE TERRAIN (ESPECIALLY AS THE SFC-900MB FLOW BACKS MORE
SOUTHWESTERLY TOWARD 06Z) TO AT LEAST PROVIDE THE POSSIBILITY FOR
SOME STRATUS DEVELOPMENT OVER THE HIGHER TERRAIN. BIGGEST CHALLENGE
REMAINS QUITE DRY AIRMASS WITH LITTLE IN THE WAY OF RECOVERY
EXPECTED. AS SUCH...WILL HINT AT LOW CLOUD POTENTIAL IN THE FCST BUT
REFRAIN FROM GOING CRAZY LIKE RECENT RUNS OF THE NAM WOULD SUGGEST.
CERTAINLY NOT A HUGE DEAL...BUT SOMETHING TO WATCH IN AN OTHERWISE
RATHER BORING STRETCH OF WX.
THU STILL SHAPING UP TO BE A RATHER NICE DAY (HOPEFULLY WITH NO LOW
CLOUD ISSUES EARLY)...WITH MODEST MIXING IN ADVANCE OF ARCTIC COLD
FRONT SLIDING THRU ONTARIO LIKELY HELPING PROMOTED A RATHER WARM
DAY. GOING FCST HIGHS WELL INTO THE 30S LOOKS JUST FINE...WITH A FEW
SPOTS LIKELY TO REACH 40...ESPECIALLY UP THE SPINE OF NORTHWEST
LOWER AND MAYBE FAR NORTHEAST LOWER. THINGS ALL CHANGE RAPIDLY
BEGINNING THU NIGHT AS RAPID AMPLIFICATION OF WESTERN NORTH AMERICAN
RIDGING (ALREADY ONGOING THIS MORNING) DISLODGES THE POLAR VORTEX
DOWN TOWARD ITS MUCH MORE CLIMO-FAVORED LOCATION AROUND HUDSON BAY.
AMPLIFYING UPPER TROUGH DROPPING INTO THE REGION AS THIS OCCURS WILL
DRIVE AN ARCTIC COLD FRONT THRU THE CWA BETWEEN ROUGHLY 04Z AND
12Z...WITH A QUICK UPTICK IN MOISTURE AND DEEP LAYER QG UPWARD
FORCING (FOR A BRIEF TIME) HELPING KICK OFF A ROUND OF POST-FRONTAL
SNOW SHOWERS. IN LINE WITH EARLIER FCST...WILL CONTINUE TO CARRY
ABOUT AN INCH IN MANY SPOTS...WITH THE LEAST AMOUNTS CLOSER TO
SAGINAW BAY WHICH WILL BE MORE REMOVED FROM THE DEEPEST MOISTURE AND
BEST FORCING. COULD PERHAPS SEE A FEW 2 INCH AMOUNTS GIVEN BRIEF
PERIOD OF FAVORABLE SNOWFLAKE GROWTH WITH A QUICKLY DEEPENING DGZ IN
THE PRESENCE OF STRONG COLD ADVECTION.
SYNOPTIC PERIOD OF SNOW WILL END QUICKLY BY FRIDAY MORNING...WITH
FOCUS SHIFTING TO LAKE EFFECT AS VERY COLD AIRMASS SETTLES IN
OVERHEAD...WITH H8 TEMPS DIVING TO AROUND -22C...GIVE OR TAKE A FEW
DEGREES. MEAN LOW LEVEL FLOW CONTINUES TO LOOK QUITE NORTHERLY THRU
THE DAY ON FRI...FAVORING LOCATIONS DOWNWIND OF GRAND TRAVERSE BAY
WITH THE BEST CHANCES FOR SNOW SHOWERS. ACTUALLY WOULD NOT BE
SURPRISED TO SEE THE FLOW ACTUALLY END UP MORE NORTHEAST GIVEN
STRENGTH OF RIDGING FOLDING INTO THE AREA...WHICH WOULD FURTHER
REMOVE MUCH OF THE CWA FROM DECENT SNOW SHOWER CHANCES. EITHER
WAY...DESPITE DECENT DEPTH OF MOISTURE UP TO AROUND 850MB...STRONG
HINTS OF INVERTED-V NEAR SURFACE LAYER AND MAJORITY OF CLOUD DEPTH
BELOW THE DGZ WILL FAVOR BOTH SMALL FLAKE AND ONLY LIGHT
ACCUMULATIONS OF PERHAPS AN INCH OR TWO. MEANWHILE...EXPECT SKIES
WILL CLEAR INLAND ON EXPECTED NORTHERLY FLOW REGIME...AND WILL
RATCHET DOWN CLOUD COVER SIGNIFICANTLY ALONG THE I-75 CORRIDOR.
CERTAINLY MUCH COLDER (THAT'S AN UNDERSTATEMENT)...WITH HIGHS SINGLE
DIGITS NORTH TO LOWER/MIDDLE 20S SOUTH EARLY. READINGS WILL FALL
THRU THE DAY. LITTLE CHANGE INTO FRI NIGHT...THOUGH WITH BACKING
FLOW MORE NORTHWESTERLY LIKELY KICKING SOME LIGHT SNOW SHOWERS BACK
INTO NORTHWEST LOWER AND NORTHERN CHIPPEWA COUNTY. SHOULD BE A COLD
NIGHT...WITH MANY INTERIOR LOCATIONS BELOW ZERO AS DRAINAGE FLOW OFF
ONTARIO DOMINATES FOR A TIME.
LAWRENCE
EXTENDED FORECAST (SATURDAY THROUGH TUESDAY): MAIN CENTERS OF ACTION
ON THE HEMISPHERIC SCALE ARE POLAR VORTICES OVER EASTERN SIBERIA AND
IN THE VICINITY OF BAFFIN ISLAND. MUCH OF THE HEMISPHERIC FLOW IS
CIRCULATING AROUND THESE TWO FEATURES...WITH LONG WAVE TROUGHING
ALSO EVIDENT OVER THE EASTERN PACIFIC. FLOW SPLITS ACROSS WESTERN
NORTH AMERICA...NORTHERN BRANCH FLOW CUTTING THROUGH HIGH LATITUDE
BLOCKING PATTERN...DOWN AROUND BAFFIN ISLAND POLAR VORTEX AND JUST
CLIPPING THE UPPER GREAT LAKES THIS MORNING. LOBE OF COLD AIR
COMING AROUND THAT UPPER LOW WILL PUSH INTO THE GREAT LAKES FOR THE
END OF THE WEEK...WHICH MEANS SATURDAY STARTS OUT THE WEEKEND COLD.
850MB TEMPERATURES IN THE -15C TO -20C RANGE WILL BRING SOME CHANCES
FOR LAKE EFFECT SNOW SHOWERS SATURDAY...THOUGH LOW LEVEL WINDS MAY
BE A BIT SQUIRRELY AROUND EASTERN SIDE OF ARCTIC HIGH DROPPING
SOUTHEAST ACROSS THE PLAINS STATES. SOME SIGNALS FOR NORTHWEST FLOW
LOW LEVEL WARM ADVECTION DEVELOPING AROUND THE EAST SIDE OF THIS
HIGH FOR SATURDAY NIGHT INTO SUNDAY. THIS COULD ALLOW FOR A LITTLE
MORE WIDESPREAD SNOWFALL ACROSS THE REGION...OR AT THE VERY LEAST
ENHANCE ONGOING LAKE CONVECTION. MODERATING TEMPERATURES SHOULD
TEMPER THE SNOW THREAT HEADING INTO MONDAY...BUT CONTINUED SPLIT
FLOW ACROSS THE WESTERN STATES WITH AN ACTIVE SOUTHERN BRANCH WILL
GET INTO THE ACT EARLY NEXT WEEK. COULD BRING SNOW BACK INTO THE
PICTURE AS EARLY AS MONDAY NIGHT/TUESDAY. THIS TYPE OF PATTERN HAS
THE POTENTIAL TO BE RATHER MISCHIEVOUS DOWN THE ROAD...SO WILL NEED
TO WATCH GUIDANCE TRENDS REGARDING EVOLUTION OF WAVES IN BOTH JET
BRANCHES FOR LATER NEXT WEEK.
AS FOR TEMPERATURES...COLD SATURDAY WITH A LOT OF HIGHS IN THE TEENS
EXPECTED...MORE WIDESPREAD 20S SUNDAY...THEN GETTING BACK INTO THE
30S FOR MONDAY/TUESDAY.
JPB
&&
.MARINE.../ISSUED AT 335 AM/
A TIGHTENING PRESSURE GRADIENT ACROSS THE GREAT LAKES REGION WILL
RESULT IN INCREASING WESTERLY WINDS THROUGH THE DAY TODAY...WITH
SMALL CRAFT ADVISORIES NEEDED ACROSS MANY NEARSHORE WATERS. WINDS
WILL BE STRONGEST THROUGH THE STRAITS WHERE CHANNELING WILL COME
INTO PLAY. SMALL CRAFT ADVISORY CONDITIONS WILL CONTINUE INTO
TONIGHT AND THURSDAY AS THE GRADIENT REMAINS TIGHT AHEAD OF AN
APPROACHING ARCTIC COLD FRONT. THERE IS THE POTENTIAL FOR A PERIOD
OF GALE FORCE WINDS ON LAKE MICHIGAN JUST AHEAD OF THIS FRONT
THURSDAY AFTERNOON AND EVENING...WITH GUSTINESS EXPECTED TO CONTINUE
RIGHT ON INTO FRIDAY EVENING AS QUITE COLD AIR PUSHES INTO THE AREA.
LAWRENCE
&&
.AVIATION.../ISSUED AT 602 AM/...VALID FOR 12Z TAFS
SOLIDLY VFR THROUGH THE TAF PERIOD WITH HIGH PRESSURE IN CONTROL.
LIGHT WINDS THIS MORNING (WITH A LITTLE WIND SHEAR AROUND APN)
WILL GIVEN WAY TO SOME GUSTINESS INTO THE AFTERNOON AS THE
PRESSURE GRADIENT TIGHTENS...BUT GUSTS SHOULD REMAIN BELOW 20
KNOTS. WINDS WILL SUBSIDE BELOW 10 KNOTS AFTER SUNSET...WITH
MAINLY CLEAR SKIES DOMINATING THROUGHOUT THE TAF PERIOD. THERE IS
A VERY SMALL CHANCE SOME LOWER STRATUS COULD DEVELOP OFF OF LAKE
MICHIGAN TONIGHT...BUT WITH VERY DRY AIR IN PLACE...THIS IS A VERY
LOW PROBABILITY OUTCOME.
LAWRENCE
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 11 AM EST FRIDAY
FOR LHZ345>347.
LM...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 11 AM EST FRIDAY
FOR LMZ323-341-342-344>346.
LS...NONE.
&&
$$
