Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 241404
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
1004 AM EDT TUE MAR 24 2015

.UPDATE...
ISSUED AT 940 AM EDT TUE MAR 24 2015

MODELS ARE IN PRETTY GOOD AGREEMENT ON THE STORM TRACK GOING
THROUGH NORTHERN LOWER MICHIGAN...BUT THE EXACT STORM TRACK WILL
DEPEND ON WHAT PRECIPITATION TYPE FALLS...WHERE...AND HOW MUCH.
LATEST MODEL RUNS APPEAR TO BE COOLER...POSSIBLY CHANGING OVER TO
SNOW INSTEAD OF RAIN AFTER ANY FREEZING RAIN THAT FALLS DURING THE
LATE OVERNIGHT HOURS AND INTO THE MORNING. WILL WAIT FOR THE NEXT
MODEL RUNS TO COME IN TO MAKE ANY CHANGES THAT MAY BE NEEDED.

&&

.NEAR TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 445 AM EDT TUE MAR 24 2015

SYNOPTIC PATTERN AND OBSERVATIONS:

EARLY THIS MORNING...ALL IS QUIET. SKIES BECOMING CLEAR FROM
REMNANT HIGHER CLOUD DUE TO A DEPARTING SHORTWAVE. THE AIR MASS IS
VERY DRY...WITH 00Z APX SOUNDING SHOWING 0.14" PWAT...ALTHOUGH
THIS WAS MAINLY ALOFT AND THOSE CLOUDS ARE LEAVING. PWATS NOW EVEN
LOWER. WE ACTUALLY HAVE MID LEVEL RIDGING AND SUBSIDENCE SETTLING
INTO THE REGION. TEMPERATURES WERE CHILLY...IN THE TEENS AND LOWER
20S. UPSTREAM...ATTENTION IS PAID TO A SHORTWAVE TROUGH EMANATING
FROM THE ROCKIES AND INTO THE CENTRAL PLAINS. A COUPLE OF MAIN
VORTICITY MAXIMA WERE NOTED WITHIN THE TROUGH...RESULTING IN TWO
SEPARATE AREAS OF LOW PRESSURE. ONE IS IN THE WESTERN DAKOTAS AND
THE OTHER IN KANSAS. THE GULF IS BLOCKED OFF WITH ACTUALLY A CORE
OF VERY DRY H8-H5 AIR ABOVE THE DEEP SOUTH. HOWEVER...THERE WAS A
NARROW CORRIDOR OF MOISTURE ALONG A DEVELOPING WARM FRONT AND NRN
EDGE OF STEEP LAPSE RATES OF 6-6.5C/KM...TAPPING AT LEAST SOME
MOISTURE WRAPPING IN FROM CENTRAL TEXAS. A LLJ WAS HELPING TO
RESULTING IN AN AREA OF SHOWERS AND SOME THUNDERSTORMS ALONG/NEAR
THAT WARM FRONT. LESS MOISTURE WITH THE NRN LOW...BUT SOME DPVA
AND UPPER DIVERGENT SUPPORT WAS ABLE TO SPARK SOME MORE PATCHY
LIGHT PRECIPITATION.

SYNOPTIC PATTERN EVOLUTION AND ASSOCIATED WEATHER:

NOT MUCH AT ALL WITH THE WEATHER FOR TODAY AND THIS EVENING...AS
MID LEVEL RIDGING...SUBSIDENCE AND DRY AIR WILL RESULT IN A RATHER
SUNNY DAY. WE WILL STILL BE UNDER THE INFLUENCE OF SFC HIGH
PRESSURE THAT WILL BE JUST TO OUR EAST...EAST/SE FLOW WILL KEEP
EASTERN UPPER AND NE LOWER COOLER...IN THE LOW TO MIDDLE
30S...WHILE INLAND AREAS AND WEAK DOWNSLOPING ACROSS NW LOWER WILL
FEEL UPPER 30S AND LOWER 40S. THIS DRY AIR HOLDS THROUGH THIS
EVENING WITH ONLY SOME HIGHER LEVEL CLOUDS STARTING TO ADVANCE
INTO NRN MICHIGAN AHEAD OF THE AFOREMENTIONED SHORTWAVE TROUGHING
WHICH WILL BE MOVING INTO THE MIDDLE AND UPPER MISSISSIPPI VALLEY.
THIS TROUGH WILL BECOME INCREASINGLY NEGATIVELY TILTED...AS IT
CONTINUES TO LIFT INTO THE GREAT LAKES LATE TONIGHT INTO WEDNESDAY
MORNING. DPVA/WAA/UPPER DIVERGENCE ALL LEAD TO RESPECTABLE DEEP
LAYER -DIVQ...AHEAD OF THE SFC LOW PRESSURE...WARM FRONT AND
LEADING EDGE OF STEEPER MID LEVEL LAPSE RATES. SKIES WILL QUICKLY
BECOME CLOUDY IN RAPID MOISTENING...WITH A BAND OF PRECIPITATION
WITH POSSIBLE CONVECTIVE/SHOWERY ELEMENTS EMBEDDED WITHIN. THIS
BAND OF PRECIPITATION WILL LIFT FROM SW TO NE THROUGH MAINLY THE
MORNING...ALTHOUGH LINGERING ECHOES EXPECTED ACROSS EASTERN UPPER
ASSOCIATED WITH INCOMING VORT MAX HELPING FORCING ALONG DEPARTING
SFC LOW AND NEARING COLD FRONT.

MORE DETAILS...PRECIP TYPE...EARLIER DISCUSSIONS HAVE THE TREND
CORRECT...BUT A COLDER SCENARIO FURTHER SOUTH IS LOOKING TO RESULT
IN A PERIOD OF SNOW AT THE INITIAL ONSET OF PRECIPITATION FOR
MORE OF NRN LOWER. THE WARM ADVECTION BRINGS >+0C WARM NOSE OF AIR
AT AROUND 850MB TO NRN LOWER...BUT INITIAL ONSET OF PRECIPITATION
IN VERY DRY AIR AND LOW WET BULBS TO RESULT IN A PRIMARILY SNOW
ONSET OF PRECIP. EXACT TRACK OF THE SFC LOW IS VITAL FOR THE
DEPICTING THE EVOLUTION OF THE PRECIPITATION TYPE (FURTHER SOUTH
COULD LEAD TO MORE SNOW...FURTHER NORTH A STRONGER WARM NOSE AND
FREEZING RAIN POTENTIAL. THE FREEZING RAIN POTENTIAL IS ENHANCED
BY LATE NIGHT ARRIVAL OF PRECIPITATION WITH SFC ROAD TEMPS LIKELY
TO FALL BELOW ZERO DUE TO A CHILLY START WITH TEMPS FALLING IN
CLEAR SKIES. ALTHOUGH THERE REMAINS SOME UNCERTAINTY...FOLKS
SHOULD STILL PLAN FOR A MIX OF SNOW...RAIN AND FREEZING RAIN FOR
MOST ALL OF NRN LOWER...WHILE THIS STILL LOOKS LIKE PRIMARILY
SNOW FOR EASTERN UPPER OF 1-3 INCHES.

THE SYSTEM DRY SLOW/DRYING ALOFT ARRIVES THROUGH WEDNESDAY
AFTERNOON WHILE SFC TEMPS CLIMB INTO THE MIDDLE 30S IN EASTERN
UPPER FOR MORE OF A LIGHT RAIN/SNOW...AND INTO THE UPPER 30S AND
EVEN POSSIBLE MIDDLE 40S ACROSS PARTS OF NE LOWER. THIS WILL END
ALL FREEZING ISSUES...AND RESULT IN A LIGHT RAIN/DRIZZLE FEEL IN
NRN LOWER.

IMPACTS: OBVIOUSLY THE ICING POTENTIAL WITH AROUND A TENTH OF AN
INCH POSSIBLE. THIS IS WELL ENOUGH TO PROVIDE SIGNIFICANT CONCERNS
DUE TO ICY/SLIPPERY ROADS. UNCERTAINTIES WITH SFC ROAD TEMPS AND
EVOLUTION OF THE PRECIP TYPE WILL PREVENT ANY HEADLINES AT THIS
POINT. SCHOOL CLOSURES CERTAINLY POSSIBLE AND SLOWER COMMUTES TO
WORK. EASTERN UPPER WILL ALSO HAVE SOME SLIPPERY CONDITIONS BUT
MAINLY JUST DUE TO LIGHT SNOW ACCUMULATIONS.

&&

.SHORT TERM...(WEDNESDAY NIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 445 AM EDT TUE MAR 24 2015

WEDNESDAY NIGHT AND THURSDAY...THE STORM SYSTEM WHICH LIFTED INTO
THE GREAT LAKES EARLY WEDNESDAY...WILL LIFT NORTHEAST TOWARD QUEBEC
WEDNESDAY NIGHT BEFORE FINALLY EXITING EAST OF THE STATE THURSDAY
NIGHT. AT UPPER LEVELS...NEARLY ZONAL 500MB FLOW WEDNESDAY WILL BE
REPLACED BY A SHARP DIGGING UPPER TROUGH SETTLING INTO THE GREAT
LAKES THURSDAY NIGHT. THIS PATTERN WILL HELP USHER IN ANOTHER ROUND
OF COOL TEMPS ACRS NRN MI...AS 850MB TEMPS FALL FROM ARND +1C
WEDNESDAY TO AROUND -6C WEDNESDAY NIGHT AND FINALLY TO -16C BY
THURSDAY NIGHT. THIS PATTERN WILL FORCE AFTERNOON HIGH TEMPS BACK
INTO THE MID 30S FOR MUCH OF NRN MICHIGAN BY THURSDAY. CHANCES OF
PCPN WILL LINGER ACRS NRN MI THROUGH THE PERIOD AS SFC AND UPPER
LVL FEATURES SLOWLY EXIT EAST OF THE REGION. WILL MENTION PCPN
MAINLY IN THE FORM OF SNOW WEDNESDAY NIGHT AND THURSDAY. HOWEVER A
PERIOD OF DRIZZLE OR FREEZING DRIZZLE WOULD NOT BE OUT OF THE
QUESTION WEDNESDAY NIGHT...AS MODEL SOUNDINGS AND MSTR PROGS SHOW
EXTREMELY DRY MID LVLS FORMING BTWN 00Z AND 12Z THURSDAY.
850/500MB RH DRIES TO UNDER 30PCT WHILE LOW LVLS REMAIN SATURATED
AND WARMER THAN -10C...WITH SOME WIND SHEAR PRESENT AT THE TOP OF
THE LOW LVL INVERSION.

&&

.LONG TERM...(FRIDAY THROUGH MONDAY)
ISSUED AT 445 AM EDT TUE MAR 24 2015

WILL BE A FAIRLY ACTIVE PERIOD ACROSS THE GREAT LAKES AS ONE
STORM SYSTEM EXITS EAST FRIDAY...WHILE A SECOND CLIPPER SYSTEM
PUSHES ACROSS THE STATE SUNDAY. AT UPPER LEVELS...A DEEP 500MB
TROUGH OVER THE ERN LAKES FRIDAY WILL EXIT TO THE ATLANTIC
COAST...WHILE A WEAK UPPER RIDGE BUILDS INTO THE STATE SATURDAY IN
ADVANCE OF AN APPROACHING 500MB LOW FCST TO SWEEP OVER THE STATE
SUNDAY. OVERALL LOOKING AT BELOW NORMAL TEMPERATURES ACRS NRN MI
THROUGH THE PERIOD WITH SOME CHANCES FOR PCPN.

EXPECT MAINLY DRY CONDS ACRS NRN MI FRIDAY AND SATURDAY AS A LARGE
AREA OF HIGH PRESSURE SETTLES INTO THE GREAT LAKES AND OHIO VALLEY.
HOWEVER WILL MENTION A FEW SNOW SHOWERS LINGERING ALONG THE LAKE
MICHIGAN SHORELINE FRIDAY...THE RESULT OF SFC-850MB NW WINDS AND
850MB TEMPS FALLING TO -20C. ANOTHER CHANCE OF PCPN RETURNS TO THE
REGION SUNDAY...AS SFC AND UPPER LVL FEATURES SWEEP OVER THE PLAINS
AND INTO THE GREAT LAKES. MIXED RAIN AND SNOW IS POSSIBLE SUNDAY AS
850MB TEMPS WARM TO BTWN 0C AND 2C IN ADVANCE OF APPROACHING
FEATURES. TRENDING DRY MONDAY AS AREA OF HIGH PRESSURE SETTLES BACK
INTO THE GREAT LAKES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 634 AM EDT TUE MAR 24 2015

...WINTRY WEATHER LATE TONIGHT...

HIGH PRESSURE TO OUR NE WILL CONTINUE TO DOMINATE OUR WX. A VERY
DRY ATMOSPHERE WILL LEAD TO SUNNY SKIES TODAY. LOW LEVEL MOISTURE
IS VERY LIMITED...AND LITTLE IS EXPECTED IN THE WAY OF CUMULUS.
SKIES WILL RAPIDLY BECOME CLOUDY LATE TONIGHT WITH CHANCES FOR
SNOW TOWARD DAYBREAK. TVC/MBL...FREEZING RAIN/SLEET ARE EXPECTED
TO DEVELOP AFTER 08Z.

LIGHT EAST/SE WINDS INCREASING TO 6-8KTS TONIGHT.


&&

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

$$

UPDATE...TJL
NEAR TERM...SMD
SHORT TERM...SWR
LONG TERM...SWR
AVIATION...SMD


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