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000
FXUS63 KAPX 221205
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
805 AM EDT WED MAY 22 2013


.SYNOPSIS...
ISSUED AT 339 AM EDT WED MAY 22 2013

LOW PRESSURE WILL SLOWLY MOVE ACROSS THE AREA TODAY AND TONIGHT...
GENERATING WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS...
ESPECIALLY ACROSS NORTHERN LOWER MICHIGAN. LARGE AND SLOW MOVING
HIGH PRESSURE BUILDS INTO THE AREA LATER THURSDAY...REMAINING
OVERHEAD RIGHT THROUGH THE UPCOMING HOLIDAY WEEKEND. THIS SYSTEM
WILL BRING COOL LATE MAY AIR...ALONG WITH PLENTY OF SUNSHINE.

&&

.UPDATE...
ISSUED AT 800 AM EDT WED MAY 22 2013

PATCH OF LIGHT RAIN AND SPRINKLES NOW HEADING UP ACROSS PORTIONS
OF NE LOWER...TIMING STILL GOOD...JUST NEED TO REFINE THE POP
GRIDS. STILL LOOKING FOR RAIN TO FILL IN ACROSS THE MAJORITY OF
NRN LOWER ALONG AND SOUTH OF A TVC-ALPENA LINE BY MIDDAY...AS
UPPER SUPPORT/FORCING STRENGTHEN. AREAS OF DENSE FOG STILL
HANGING IN THERE...BUT AREA OBS SHOWING THAT WIDESPREAD DENSE FOG
IS BECOMING LESS LIKELY. THAT TREND WILL CONTINUE THROUGH THE
MORNING. THE DENSE FOG ADVISORY WILL BE ALLOWED TO EXPIRE.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 339 AM EDT WED MAY 22 2013

CURRENTLY...PESKY UPPER LOW IS SPINNING OVER WESTERN MN WITH
ASSOCIATED SFC LOW IN FAR NRN IL. LOW LEVEL TROUGHING EXTENDS FROM
THIS LOW PRESSURE ACROSS NRN LOWER MICHIGAN. A LIGHT EASTERLY
FLOW NORTH OF THIS TROUGHING...AND MOIST AIR OVER THE COLD LAKE
WATERS...CONTINUES TO RESULT IN WIDESPREAD LOW CLOUDS...ALONG WITH
AREAS OF DENSE FOG FOR A GOOD CHUNK OF FAR NRN LOWER MICHIGAN AND
PORTIONS OF MACKINAC COUNTY IN EASTERN UPPER. A DENSE FOG ADVISORY
HAS BEEN ISSUED. LOOKING BACK TO THE SOUTH...AND NEAR THE LOW
PRESSURE...THERE WERE SHOWERS AND SOME STORMS FIRING OFF ALONG THE
TROUGHING...FROM CENTRAL IL...TO AS FAR NORTH AS SW LOWER
MICHIGAN. THESE SHOWERS HAVE BEEN ABLE TO FIRE WITH THE ASSISTANCE
OF INCREASING UPPER LEVEL DIFFLUENT FLOW AND INCREASING -DIVQ IN
WEAK SHORTWAVE ENERGY EJECTING FROM THE UPPER LOW.

THROUGH DAYBREAK...AREAS OF DENSE FOG WILL GRADUALLY LIFT/THIN
ENOUGH FOR THE ADVISORY TO END AROUND 8AM. THICKENING CLOUDS IN
ADVANCE OF THE DEVELOPING SHOWERS WILL ASSIST MINIMAL SFC HEATING
TO IMPROVE VISIBILITIES. AREAS OF DENSE FOG WILL STILL CONTINUE TO
FLOAT AROUND THE COASTAL AREAS WHERE T/TD DEPARTURES WILL BE
MINIMAL.

AS WE HEAD THROUGH THE DAY AND NIGHT...STRONGER SHORTWAVE ENERGY
WILL LIFT NE AND INTO LOWER MICHIGAN WITH SLIGHTLY DEEPENING SFC
LOW PRESSURE THAT WILL CROSS THE THUMB LATE TONIGHT. NOT EXPECTING
A WHOLE LOT OF HEATING TODAY WITH CLOUDY SKIES BEING RATHER
DOMINANT. HIGH TEMPERATURES WILL MAINLY BE IN THE 60S TODAY WHICH
WILL LEAVE MUCH TO BE DESIRED ON THE INSTABILITY FRONT. ONLY A FEW
HUNDRED J/KG ARE EXPECTED...AND WILL OPT TO ONLY MENTION SOME
ISOLATED THUNDERSTORMS FOR THE DAY...WITH SEVERE STORMS NOT
EXPECTED. AS STRONGER SHORTWAVE ENERGY ARRIVES...SO DOES A NICE
POCKET OF UPPER DIVERGENCE ASSOCIATED WITH A DOUBLE JET STRUCTURE
ALOFT. THE OVERALL FORCING INCREASES TODAY...AND AM FULLY
EXPECTING THE RADAR TO FILL IN WITH PERIODS OF/FAIRLY STEADY
SHOWERS...AGAIN WITH SOME EMBEDDED THUNDER. AN INTERESTING FEATURE
OF NOTE...IS A STRONG NRN STREAM SHORTWAVE AND COLD FRONT DROPPING
SOUTH OUT OF FAR NRN ONTARIO. WITH MERGING SHORTWAVE ENERGY...A
NOTICEABLE BAND OF ENHANCED PRECIPITATION IS LIKELY WITHIN
DEVELOPING/STRENGTHENING LOW TO MID LEVEL FGEN. CAN SEE AN AXIS OF
HIGHER QPF ALIGNING ITSELF ACROSS NRN LOWER LATER TODAY AND INTO
TONIGHT...FROM MANISTEE THROUGH GAYLORD AND OFF TOWARD ROGERS
CITY/ALPENA. UNCERTAIN AS TO HOW MUCH PRECIPITATION GETS INTO
EASTERN UPPER...AS THE DOWNWARD BRANCH OF THE FGEN WILL LIKELY
LEAD TO A SHARPER PRECIPITATION CUT OFF. MOST OF NRN CHIPPEWA
COUNTY...POSSIBLY ALL OF CHIPPEWA COUNTY...COULD BE RAIN FREE.
THESE DETAILS WILL HAVE TO BE HAMMERED OUT ON A MORE SHORT TERM
BASIS. THE OW PRESSURE WILL EXIT NRN LOWER TOWARD THURSDAY
DAYBREAK...BUT RAINS WILL LIKELY PERSIST THROUGH THE NIGHT ACROSS
NRN LOWER.

A TIGHTENING PRESSURE GRADIENT ON THE BACKSIDE OF THE DEPARTING
LOW...WILL BRING GUSTIER NORTHERLY WINDS AND COLD ADVECTION. FOLKS
ACROSS EASTERN UPPER AND FAR NRN/NW LOWER MICHIGAN...ESPECIALLY
DOWNWIND OF THE GREAT LAKES WILL EXPERIENCE FAIRLY GUSTY WINDS.
THIS INCREASED WIND WILL ALLOW FOG TO BECOME AN INCREASINGLY NON-
ISSUE FROM NORTH TO SOUTH THROUGH THE NIGHT.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 339 AM EDT WED MAY 22 2013

THURSDAY...AS THE DAY STARTS OUT THE 500 MB TROUGH AXIS WILL STILL
BE OVERHEAD, AND WITH THE DEFORMATION ZONE ON THE NE SIDE OF THE SFC
LOW WILL EXPECT THAT RAIN SHOWERS WILL BE AROUND. HOWEVER, AS THE
500 MB TROUGH DROPS SE, THE DRY AIR BEHIND IT WILL BEGIN TO CLEAR
THE SKY FROM NW TO SE THROUGH THE DAY. THE TEMPERATURES WILL END UP
BEING CHILLY AS THE 850 MB TEMPERATURES APPROACH 0C BY 00Z. THE ONLY
THING THAT WE HAVE GOING FOR US WILL BE THE MOSTLY SUNNY SKY IN THE
AFTERNOON AS THE RH IN THE LOWER AND MID LEVELS OF THE ATMOSPHERE
DRY OUT TO AROUND 10%. THIS WILL ALLOW US TO WARM UNDER FULL SUN.
WITH THE SFC HIGH BUILDING IN THE REGION, WINDS SHOULD BEGIN TO
SETTLE DOWN A BIT AS THE GRADIENT BEGINS TO SLACKEN BY EVENING.

THURSDAY NIGHT...AS THE TEMPERATURES DIP TOWARD FREEZING, AND THE
WINDS DIMINISH, WILL EXPECT THAT FROST WILL BE AN ISSUE. AT THIS
POINT, HAVE PATCHY AND AREAS OF FROST, BUT IT MAY HAVE TO BE WIDENED
AS THE TEMPERATURES HAVE A CHANCE TO FALL BELOW FREEZING. AT THIS
POINT, THE MODELS ARE POINTING AT THE SFC TEMPERATURES FALLING TO A
COUPLE DEGREES EITHER SIDE OF FREEZING AROUND MOST OF N MICHIGAN (E
UPPER AND N LOWER). THINK THAT FROST ADVISORY WILL BE UPCOMING, BUT
AT THIS POINT WITH THE GRADIENT WINDS HIGH ENOUGH, THINK THAT THE
BOUNDARY LAYER WON`T ENOUGH FOR A WIDESPREAD FREEZE WARNING. SO NO
HEADLINE AT THIS POINT.

FRIDAY...HIGH PRESSURE CONTINUE OVER THE REGION AND KEEPS THE
FORECAST AREA DRY. THE 850 MB TEMPERATURES BEGIN TO RECOVER SOME
DURING THE DAY REACHING +2C OVER MOST OF THE FORECAST AREA BY 00Z.
LOOKING AT THE MODEL SOUNDINGS BOTH THE GFS AND THE ECMWF MIX AROUND
850 MB. SO HAVE TEMPERATURES RISING TO EITHER SIDE OF 60 WITH FULL
SUN AND MIXING TO 850 MB WOULD YIELD THOSE TEMPERATURES. OVERNIGHT,
LOOKS LIKE ANOTHER POSSIBLE FROST NIGHT, ALTHOUGH NOT AS WIDESPREAD
AS WOULD BE THOUGHT. BOTH THE GFS AND ECWMF ARE SUGGESTING THAT
THERE COULD BE SOME CLOUD COVER, SO THAT FOR THE MOST PART, THE
TEMPERATURES WOULDN`T FALL AS FAR, AND THE 850 MB TEMPERATURES ARE A
LITTLE WARMER THAN THEY WERE ON THURSDAY NIGHT.

EXTENDED (SATURDAY THROUGH TUESDAY)...SATURDAY, THE HIGH PRESSURE
REMAINS IN PLACE AND CONTINUES TO KEEP THE PLACE DRY. SUNDAY, HIGH
PRESSURE CONTINUES, SO THE WEEKEND ITSELF LOOKS GOOD FOR GETTING
OUTSIDE. MONDAY, OVER N MICHIGAN LOOKS DRY. MODELS ARE STILL HOLDING
FIRM FOR MOSTLY SUNNY. OVERNIGHT, THE CLOUDS BEGIN TO INCREASE.
TUESDAY, THE CLOUDS KEEP INCREASING AND WITH THE SOUTH WIND, THE
LOWER 70S WOULD BE EXPECTED FOR THE DAY. THERE COULD BE SOME THUNDER
OVERNIGHT IN NW LOWER AS THE 500 MB RIDGE AXIS MOVES INTO THE
FORECAST AREA, AND BECOMES THE LEADING EDGE OF THUNDERSTORMS. WILL
HAVE ONLY A CHANCE FOR NOW, BUT IF THE MODELS CONTINUE THIS, THEN
WEDNESDAY MORNING WILL BE THE BIGGEST SHOT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 800 AM EDT WED MAY 22 2013

IFR/VLIFR CONDITIONS IN LOW CLOUD AND FOG STILL HOLDING ACROSS
PRIMARILY PLN/APN...AND PROBABLY JUST VERY BRIEFLY FOR TVC. FOG
WILL THIN/LIFT THROUGH THE DAY...BUT TAKE LONGEST AT PLN/APN WHERE
THESE AIRPORTS RESIDE NORTH OF A STATIONARY FRONT DRAPED ACROSS
NRN LOWER. PATCHY LIGHT RAIN SHOWERS WILL WORK UP TOWARD APN OVER
THE NEXT FEW HOURS...WITH MORE WIDESPREAD RAIN FILLING IN FROM
SOUTH TO NORTH LATE THIS MORNING AND THROUGH THE AFTERNOON. THESE
STEADY RAINS WILL CONTINUE THROUGH THE NIGHT...AFFECTING MAINLY
TVC/MBL AND APN...POSSIBLY PLN FOR A GOOD PERIOD TONIGHT TOO. IFR
CIGS AND MVFR VSBYS LOOK TO BE RATHER PERSISTENT ONCE THE RAINS
SET IN.

WINDS WILL REMAIN RATHER LIGHT OUT OF THE E/ENE...UNTIL LATER THIS
AFTERNOON AND TONIGHT WHEN THE PRESSURE GRADIENT PICKS UP. BY
MIDNIGHT AND LATER IN THE TAF PERIOD...GUSTS TO 20-25KTS START TO
DEVELOP.

&&

.MARINE...
ISSUED AT 339 AM EDT WED MAY 22 2013

MOIST AIR OVER THE COLD LAKE WATERS...ALONG WITH WEAK WINDS
CONTINUE TO RESULT IN AREAS OF DENSE FOG OVER MUCH OF NORTHERN
LAKE HURON...THE STRAITS AND NRN LAKE MICHIGAN. NOT EXPECTING MUCH
LESS AS WE HEAD THROUGH THE DAY...ALTHOUGH SOME IMPROVEMENT IS
EXPECTED THROUGH THE DAY. THIS FOG WILL GET SCOURED OUT LATER
TONIGHT...BUT WITH ANOTHER MARINE ISSUE DEVELOPING. A TIGHTENING
PRESSURE GRADIENT BEHIND A DEPARTING LOW PRESSURE AND ARRIVAL OF
MUCH COLDER AIR/COLD FRONT...WILL RESULT IN DECREASING STABILITY
AND POTENTIAL GALE FORCE GUSTS AND DEFINITE ADVISORY LEVEL GUSTS.
HIGH PRESSURE WORKS IN OVER THE LAKES LATE THURSDAY NIGHT AND
THROUGH FRIDAY FOR CALMER WINDS. THIS HIGH LINGERS INTO ALL OF THE
WEEKEND.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 2 AM EDT FRIDAY
     FOR LHZ345>347.
     GALE WATCH FROM LATE TONIGHT THROUGH THURSDAY AFTERNOON FOR
     LHZ348-349.
LM...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 2 AM EDT FRIDAY
     FOR LMZ341.
     GALE WATCH FROM LATE TONIGHT THROUGH THURSDAY AFTERNOON FOR
     LMZ323-342-344>346.
LS...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 2 AM EDT FRIDAY
     FOR LSZ321-322.

&&

$$

UPDATE...SD
SYNOPSIS...JL
SHORT TERM...SD
LONG TERM...JL
AVIATION...SD
MARINE...SD