Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 220658
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
258 AM EDT WED APR 22 2015

.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 256 AM EDT WED APR 22 2015

...EVEN CHILLIER WITH MORE SNOW SHOWERS...

SYNOPTIC PATTERN AND OBSERVATIONS:

EARLY THIS MORNING...LARGE SFC/UPPER LEVEL LOW PRESSURE CONTINUES TO
SWIRL OVER EASTERN ONTARIO. A TRAIN OF SFC TROUGHS AND AXIS OF
DEEPER MOISTURE ARE CIRCLING THIS LOW PRESSURE...WHILE SLOW COLD
ADVECTION CONTINUES TO LOWER TEMPERATURES ALOFT AND AT THE SFC.
STRONGER AND MORE WIDESPREAD CONVECTION/SNOW SHOWERS HAVE BEEN TIED
TO THE SFC TROUGHS...SUCH AS THE ONE THAT IS CROSSING NRN MICHIGAN
ATTM....WHICH HAD RESULTED IN A HALF INCH TO AN INCH OF SNOW IS SOME
SPOTS. LOOKING UPSTREAM...LAKE EFFECT SNOW SHOWERS HAVE FIRED OFF
OVER LAKE SUPERIOR IN -10C H8 AIR TEMPS. THIS AREA WAS ALSO
ASSOCIATED WITH THE NEXT SFC TROUGH HEADING OUR WAY. H8 TEMPS OVER
OUR NECK OF THE WOODS ARE JUST SHY OF BEING ABLE TO FIRE OFF LAKE
EFFECT (-7C TO -9C).

SYNOPTIC PATTERN EVOLUTION AND ASSOCIATED WEATHER:

CURRENT BAND OF SNOW SHOWERS IS MOVING ON EAST. ANY ADDITIONAL SNOW
SHOWERS BEHIND IT HAS BEEN RATHER ISOLATED...WITHOUT COLD ENOUGH
TEMPS FOR LAKE EFFECT. DOUBT THIS WILL LAST LONG. BY DAYBREAK OR
SHORTLY THEREAFTER...OVERLAKE CONVECTION SHOULD START TO INCREASE
AND MOVE INTO PARADISE IN CHIPPEWA COUNTY AND NW LOWER...VIA
WESTERLY WINDS. INSTABILITY IS STILL MUCH GREATER THAN THE WIND
SHEAR...SO MORE CELLULAR ACTIVITY IS EXPECTED RESULTING IN BURSTS OF
HEAVIER SNOW. AS DAYTIME PROGRESSES...OVERLAND INSTABILITY WILL
LIKELY FOCUS THE BETTER SNOWS INLAND...BUT DELTA T`S IN AND AROUND
13C WILL STILL LIKELY PRODUCE ACTION DOWNWIND OF LAKE SUPERIOR AND
LAKE MICHIGAN. THE AFOREMENTIONED NEXT SFC TROUGH WILL ARRIVE IN THE
MORNING...LIKELY ENHANCING SNOW SHOWERS. HIGH TEMPERATURES WILL BE
IN THE MIDDLE 30S TO LOWER 40S...BUT AS SHOWERS MOVE OVERHEAD...MUCH
COLDER AIR WILL GET CONVECTIVELY DRAWN TOWARD THE SFC. PLUS...SOME
EVAPORATIVE COOLING/WET BULBING EFFECTS WILL ALSO DRAW TEMPS DOWN
QUICKLY BE SEVERAL DEGREES. THUS...MOST ALL OF THE SHOWERS WILL BE
SNOW...WITH LITTLE IN THE WAY OF RAIN MIXING IN....BESIDES AREAS
CLOSE TO THE LAKE HURON SHORE.

THE DIURNALLY DRIVEN INLAND SNOW SHOWERS WILL SLOWLY WEAKEN INTO
THIS EVENING...WHILE THE WESTERLY WINDS WILL FOCUS SNOWS COMING IN
OFF THE LAKES AGAIN FOR THE REMAINDER OF TONIGHT. SNOW AMOUNTS ARE
DIFFICULT...DEPENDENT ON SNOW SHOWER INTENSITY TO OVERCOME STILL
MILDER GROUND TEMPERATURES...AND ALSO THE CELLULAR NATURE OF THE
SNOWS. ALL THAT SAID...TRACE AMOUNTS ACROSS FAR NE LOWER...TO AN
INCH OR PERHAPS AN INCH AND A HALF FOR HIGHER TERRAIN AREAS IN
INTERIOR NRN LOWER SHOULD BE COMMON.

LOWS TONIGHT WILL BE IN THE MIDDLE TO UPPER 20S.

&&

.SHORT TERM...(THURSDAY THROUGH FRIDAY NIGHT)
ISSUED AT 256 AM EDT WED APR 22 2015

HIGH IMPACT WEATHER POTENTIAL: NOTHING

PATTERN SYNOPSIS/ANTICIPATED EVOLUTION: ONE IMPRESSIVE LATE SEASON
TROUGH AXIS WILL BE IN SLOW RETREAT MODE HEADING THROUGH THE LATE
WEEK...LOOKING INCREASINGLY LIKELY PER TRENDS TO BE FAR ENOUGH EAST
TO LOSE ITS INFLUENCE ON OUR WEATHER BY THE WEEKEND. WEATHER SETTLES
DOWN SUBSTANTIALLY AS A RESULT...WITH HIGH PRESSURE DOMINATING OUR
WEATHER RIGHT INTO THE BEGINNING OF NEXT WEEK.

PRIMARY FORECAST CONCERNS/CHALLENGES: REALLY NOTHING SIGNIFICANT.
ADDRESSING LINGERING LIGHT RAIN/SNOW SHOWER THREAT THURSDAY.
TEMPERATURE TRENDS THROUGHOUT THE FORECAST.

DETAILS: LINGERING MOISTURE/COLD THERMAL PROFILES CONTINUES TO
SUPPORT A FEW RAIN/SNOW SHOWERS THURSDAY...ESPECIALLY ACROSS
NORTHWEST LOWER AND EASTERN UPPER MICHIGAN. LOWERING INVERSION
HEIGHTS AND NO APPRECIABLE LARGER SCALE FORCING SHOULD KEEP SHOWERS
SCATTERED AND RAIN/SNOW AMOUNTS VERY LIGHT. MOISTURE CONTINUES TO
WANE AND OVERHEAD THERMAL ENVIRONMENT CONTINUES TO WARM HEADING INTO
THURSDAY NIGHT AND FRIDAY AS HIGH PRESSURE BUILDS INTO THE
REGION...RESULTING IN DRY CONDITIONS. MAY EVEN SEE SOME DECENT
AMOUNT OF SUNSHINE FRIDAY...WHICH WILL MAKE HIGHS IN THE 40S SEEM
JUST A TOUCH WARMER.

&&

.LONG TERM...(SATURDAY THROUGH TUESDAY)
ISSUED AT 256 AM EDT WED APR 22 2015

AS MENTIONED EARLIER...NOW STRONG GUIDANCE SUPPORT HIGH PRESSURE
WILL DOMINATE OUR WEATHER RIGHT THROUGH THE WEEKEND INTO THE START
OF NEXT WEEK...SHUNTING NEXT WESTERN WAVE WELL OFF TO OUR SOUTH.
MAY SEE THE NEXT SYSTEM TAKE A RUN INTO OUR AREA BY
TUESDAY..ALTHOUGH GIVEN HOW SLOW THE WHOLE PATTERN IS
EVOLVING...GOTTA WONDER IF THIS IS TOO PESSIMISTIC. ALTHOUGH
TEMPERATURES WILL REMAIN BELOW NORMAL...OVERALL AIRMASS WILL
MODIFY SIGNIFICANTLY...ALLOWING HIGHS TO REACH MOSTLY INTO THE 50S
(SLIGHTLY COOLER SATURDAY).

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 141 AM EDT WED APR 22 2015

...PREDOMINANTLY MVFR...

THE COMBINATION OF SEVERAL SFC AND MID LEVEL TROUGHS...IN
CONJUNCTION WITH CONTINUALLY COLDER AIR...WILL RESULT IN PERIODS
OF SNOW SHOWERS ACROSS THE TAF SITES. THESE SNOW SHOWERS WILL
LIKELY BE MORE COMMON ACROSS THE NW LOWER AIRPORTS...IN WNW FLOW.
THERE WILL CERTAINLY BE PERIODS OF VFR...BUT ALSO BRIEF PERIODS OF
IFR ARE POSSIBLE IN SNOW SHOWERS. MVFR IS EXPECTED TO BE THE MORE
PREVAILING CONDITION HOWEVER.

WESTERLY WINDS WILL ALSO BE GUSTY...MAINLY THIS AFTERNOON/EVENING.


&&

.MARINE...
ISSUED AT 256 AM EDT WED APR 22 2015

LOW PRESSURE IN ONTARIO AND DECENT PRESSURE GRADIENT OVER NRN
MICHIGAN WILL COMBINE WITH GROWING OVERLAKE INSTABILITY THROUGH
TONIGHT...TO PRODUCE LOW END/MARGINAL SMALL CRAFT ADVISORY
CONDITIONS. THESE ARE LIKELY FOR PERIODS OF TIME ACROSS ALL
NEARSHORE WATERS AND THUS THE ADVISORY EXPANDED TO ALL AREAS. AIDING
THE HIGHER GUSTS WILL BE CONVECTIVE SNOW SHOWERS DRAWING DOWN THE
STRONGER WINDS ALOFT.

ADVISORY CONDITIONS ARE LIKELY TO BE EXTENDED IN TIME FOR SOME/MANY
NEARSHORE WATERS AFTER TONIGHT...BUT LOW END NATURE OF THE WINDS
WILL PREVENT THAT ATTM.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR LHZ345>347.

     SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 8 AM EDT
     THURSDAY FOR LHZ348-349.

LM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR LMZ323-341-342-
     344>346.

LS...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR LSZ321-322.

&&

$$

NEAR TERM...SMD
SHORT TERM...MSB
LONG TERM...MSB
AVIATION...SMD
MARINE...SMD


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