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000
FXUS63 KAPX 140542
AFDAPX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
142 AM EDT TUE MAY 14 2013

.SYNOPSIS...
ISSUED AT 326 PM EDT MON MAY 13 2013

AS HIGH PRESSURE MOVES EAST OF THE GREAT LAKES...TEMPERATURES WILL
BEGIN TO MODERATE TONIGHT WITH THE APPROACH OF A WARM FRONT WHICH
WILL GENERATE A CHANCE OF SOME LIGHT RAIN OR SPRINKLES INTO TUESDAY
MORNING. THE WARM FRONT WILL WORK IN OVER NORTHERN LOWER MICHIGAN
TUESDAY NIGHT WITH SHOWERS AND THUNDERSTORMS A GOOD BET INTO
WEDNESDAY MORNING. A RATHER PLEASANT STRETCH OF WEATHER IS THEN
EXPECTED THROUGH FRIDAY WITH SEASONABLE TEMPERATURES AND DECENT
SUNSHINE. THE NEXT CHANCE OF SHOWERS AND POSSIBLE THUNDERSTORMS WILL
ARRIVE THIS UPCOMING WEEKEND.

&&

.UPDATE...
ISSUED AT 134 AM EDT TUE MAY 14 2013

TEMPERATURES FELL BELOW FREEZING ACROSS PORTIONS OF NE LOWER...A
BIT COLDER THAN FORECAST DISPLAYED...AND HAD TO TWEAK THESE DOWN.
HOWEVER...THICKENING MID AND UPPER LEVEL CLOUDS WILL BRING THESE
TEMPERATURES BACK UP OVER THE NEXT FEW HOURS. ALSO INCREASED SKY
COVER TO TOTALLY CLOUDY ALL AREAS THROUGH AT LEAST 12Z UNTIL MAYBE
SOME BREAKS CAN ARRIVE IN AND AROUND THE GTV BAY REGION...MAINLY
MANISTEE AREA. ALL-IN-ALL...FORECAST IN GOOD SHAPE.

THE PRECIPITATION WAS ERODING FAST ON THE LEADING EDGE OF THE RAIN
SHIELD....DUE TO VERY DRY LOW LEVEL AIR. 00Z APX SOUNDING SHOWING
HOW DRY...0.22" PWATS AND ALL OF THE DRY AIR BELOW 550MB. OF
COURSE WE ARE SATURATING TOP-DOWN...BUT NOT ENOUGH FOR MAINLY JUST
A FEW SPRINKLES THROUGH DAYBREAK.

UPDATE ISSUED AT 1024 PM EDT MON MAY 13 2013

CONDITIONS PRETTY MUCH WORKING OUT AS PLANNED...WITH TOP-DOWN
SATURATION WELL AHEAD OF UPSTREAM ELEVATED WARM FRONT LEADING TO
EXTENSIVE HIGH AND MID LEVEL CLOUDS. WIDESPREAD LIGHT RADAR RETURNS
ACROSS LAKE MICHIGAN AND EASTERN WISCONSIN...NONE OF WHICH APPEARS
TO BE REACHING THE SURFACE. PERUSAL OF REGIONAL SOUNDINGS EXPLAINS
WHY...WITH VERY DRY SUB H7 LEVELS. SOME SPOTTY ACTIVITY FOUND ACROSS
CENTRAL WISCONSIN...WITH SPORADIC REPORTS OF THIS REACHING THE
SURFACE. STARTING TO THINK LOW LEVEL DRY WEDGE WILL WIN OUT AS THESE
UPSTREAM SHOWERS (SPRINKLES) SPREAD EAST...A TREND WELL NOTED WITH
LATEST HI-RES GUIDANCE. INHERITED FORECAST ALREADY WILL TRENDED THIS
DIRECTION...WITH JUST LOW END SHOWER AND SPRINKLE CHANCES HEADING
TOWARDS MORNING. ANY RAIN THAT REACHES THE SURFACE WILL BE VERY
LIGHT...LIKELY PRODUCING JUST TRACE AMOUNTS. WILL CONTINUE TO
MONITOR EARLY MORNING TEMPERATURE TRENDS. CURRENT NOCTURNAL RESPONSE
WELL FORECAST BY DAY CREW. EXTENSIVE CLOUD COVER AND LIGHT WINDS
MAY PREVENT READINGS FROM FALLING AS LOW AS CURRENT FORECAST
DEPICTS. WILL CONTINUE TO FOLLOW LATEST OBS...WITH UPWARD
TEMPERATURE ADJUSTMENTS EXPECTED.

UPDATE ISSUED AT 737 PM EDT MON MAY 13 2013

CHANGES ARE FEW FOR THIS UPDATE...CENTERED ON REAL-TIME TEMPERATURE
AND CLOUD TRENDS. INITIAL WAA DRIVEN TOP-DOWN SATURATION WELL
UNDERWAY...AS EVIDENCE BY HIGH LEVEL CLOUDS RAPIDLY SPREADING ACROSS
THE NORTHERN LAKES. THIS SHOULD...THEORETICALLY...PUT A LID ON JUST
HOW COLD READINGS BECOME THIS EVENING...DESPITE CURRENT UPPER TEEN
AND LOWER 20 DEWPOINTS. TEMPERATURES SHOULD HAVE NO PROBLEM FALLING
INTO THE 30S ACROSS NORTHEAST LOWER...WITH EVEN SOME PATCHY FROST IN
THE TRADITIONAL COLDER LOCALES. EXPECT READINGS TO STABILIZE OR EVEN
WARM HEADING TOWARDS MORNING. THUS...WILL NOT ISSUE ANY FROST
HEADLINE WITH THIS UPDATE (NO DOUBT...WILL CONTINUE TO MONITOR).
UPSTREAM MID LEVEL ISENTROPIC UPGLIDE AND SOMEWHAT BETTER DEEP LAYER
MOISTURE AXIS KICKING OFF A NARROW RIBBON OF VERY LIGHT RAINS AND
SPRINKLES OVER NORTHWEST UPPER MICHIGAN DOWN INTO WISCONSIN. RAIN
AMOUNTS HAVE BEEN LIGHT AT BEST...WITH MOST LOCALES ONLY REPORTING A
TRACE. EXTRAPOLATION OF ABOVE SUPPORTS INHERITED LIGHT RAIN/SPRINKLE
MENTION LATER TONIGHT INTO TUESDAY. WILL MONITOR NEED TO BUMP UP
CURRENT LOW END CHANCES THROUGH THIS PERIOD. EITHER WAY...DEARTH OF
DEEPER MOISTURE SHOULD KEEP ANY RAIN AMOUNTS ON THE LIGHT SIDE.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 326 PM EDT MON MAY 13 2013

TONIGHT/TUESDAY...ELEVATED WARM FRONT MOVES INTO THE GREAT LAKES
WITH MAIN FORECAST ISSUES BEING PRECIPITATION CHANCES...FROST
POTENTIAL EARLY TONIGHT AND CLOUD TRENDS ON TUESDAY.

THICKENING MID/HIGH CLOUDS TONIGHT WITH INCREASING ISENTROPIC ASCENT
IN THE 300-310K LAYER. AMBIENT AIRMASS VERY DRY WITH LIMITED
MOISTURE BELOW 700MB.  SO MAIN QUESTION BECOMES...HOW MUCH
PRECIPITATION WILL ACTUALLY GET TO THE GROUND?  MOST OF THE
OVERNIGHT HOURS WILL SEE ISENTROPIC UPGLIDE GRADUALLY SATURATING THE
COLUMN FROM TOP TO BOTTOM.  BEST CHANCE FOR LIGHT RAIN/SPRINKLES
LATER TONIGHT WILL BE OVER WESTERN PORTIONS OF THE AREA.  WITH
EVENING DEWPOINTS LIKELY IN THE TEENS AND DIMINISHING WINDS...TEMPS
WILL DROP QUICKLY.  A TRICKY LOW TEMP FORECAST...AS TEMPS DROP
QUICKLY EARLY AND THEN LEVEL OFF/RISE A BIT AS CLOUDS THICKEN LATE.
I WILL DROP TEMPS TOWARD THE FREEZING MARK LATE THIS EVENING OVER
MAINLY CENTRAL/EASTERN PORTIONS OF THE AREA...THEN STEADYING THEM
OFF LATE.  COULD CERTAINLY ARGUE FOR A FROST/FREEZE HEADLINE FOR THE
EASTERN HALF OF THE AREA...BUT JUST NOT CONFIDENT ENOUGH IN
WIDESPREAD FREEZING TEMPS GIVEN INCREASING CLOUD COVER AND
DEVELOPING WEAK RETURN FLOW.

TUESDAY...UPPER LEVEL MOISTURE STRIPS OUT EARLY LEAVING BEHIND
MID/LOWER LEVEL MOISTURE INVOF WARM FRONT...RESULTING IN SOME
SPRINKLES/LIGHT RAIN.  ALL AREAS LIKELY CLOUDY THROUGH THE
MORNING...WITH CLOUDS HANGING ON WELL INTO THE AFTERNOON OVER
NORTHEAST LOWER/EASTERN UPPER NORTH OF THE FRONT.  EXPECT SKIES TO
AT LEAST PARTIALLY CLEAR OVER WESTERN AREAS /GTV BAY-SOUTHWARD/
DURING THE AFTERNOON...PUSHING TEMPS WELL INTO THE 60S IN THOSE
AREAS.  COMBINATION OF COOLER ONSHORE SOUTHEASTERLY FLOW AND CLOUDS
WILL KEEPS TEMPS MAINLY IN THE 50S OVER NORTHEAST LOWER INTO EASTERN
UPPER.  A FEW POP-UP SHOWERS POSSIBLE TUESDAY AFTERNOON WITH
APPROACH OF UPSTREAM SHORTWAVE ENERGY AND ARRIVAL OF SLIGHTLY
STEEPER MID LEVEL LAPSE RATES.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 326 PM EDT MON MAY 13 2013

TUESDAY NIGHT...THE WARM FRONT MOVES THROUGH THE REGION AND THE
OCCLUDED FRONT MOVES INTO THE UPPER GREAT LAKES. THE 500 MB LOW
ROLLS OVER THE RIDGE THAT WAS OVER THE FORECAST AREA IN THE EVENING.
WHILE ORGANIZED SEVERE WEATHER ISN`T EXPECTED WILL HAVE TO WATCH
WHAT HAPPENS OVERNIGHT AS A 850 MB JET, IN THE WARM SECTOR, WITH THE
TOTAL TOTALS INDEX GETTING INTO THE 50S, AND THE 700-500 MB LAPSE
RATES AROUND 7-8 C/KM. SO IF A STORM CAN BREAK THE CAP ALONG THE
COLD FRONT, THERE COULD BE DEEP MOIST CONVECTION WHICH WOULD LEAD TO
SEVERE POTENTIAL. AT THIS POINT, LOOKING AT THE BUFKIT SOUNDINGS,
THE MUCAPE EVEN LOOKS PRETTY WEAK. IT IS NOT LIKELY AT THIS TIME.

WEDNESDAY...THUNDERSTORMS MAY CONTINUE INTO THE MORNING AS THE
SYSTEM MOVES OUT OF THE AREA. SUBSIDENCE BRIEFLY BUILDS INTO THE
REGION POST COLD FRONTAL AND THE MAIN ACTION FORMS ALONG THE COLD
FRONT TO THE SOUTH, CUTTING US OFF FROM THE MOISTURE TRANSPORT. WITH
THE DRY AIR IN THE 700-500 MB LAYER, EXPECT THAT THE MIXING IN THE
AFTERNOON WILL LEAD TO DRY AIR AT THE SFC. WILL HAVE TO WATCH THIS
FOR FIRE WEATHER CONCERNS. WE ARE WITHIN AN THE ERROR MARGIN IN RH
AND WIND FOR A RED FLAG, TEMPERATURES CERTAINLY LOOK LIKE IT. WILL
HOLD OFF. THE MODELS ARE BEGINNING TO SIGNS OF CONVECTIVE ISSUES,
WITH NCEP TALKING ABOUT MOISTURE ISSUES IN THE GFS AND NAM (TOO
MUCH). SO THIS COULD BE AN ISSUE.

WEDNESDAY NIGHT...AS THE SFC LOW THAT MOVED THROUGH CONTINUES TO
PUSH NORTHEAST INTO QUEBEC, IT FORMS A SECOND SFC TROUGH THAT SETS
UP ANOTHER COLD FRONT WELL NORTH OF THE LAKE SUPERIOR. WITH THE COLD
FRONT THAT PUSHED THROUGH THE REGION TO THE SOUTH, THE WEAK SFC HIGH
OVER THE REGION IS ENOUGH TO CONTINUE THE DRY WEATHER.

THURSDAY...BOTH OF THE MODELS HAVE GONE DRY. HIGH PRESSURE WILL
CONTINUE OVER THE REGION WITH HIGH PRESSURE HAVING BUILT INTO THE
FORECAST AREA. OVERNIGHT, THE HIGH PRESSURE CONTINUES. SO WILL
CONTINUE THE DRY WEATHER.

EXTENDED (FRIDAY THROUGH MONDAY)...FRIDAY, FOR THE DAY IT LOOKS LIKE
THE HIGH NOSES INTO THE FORECAST AREA, AND KEEPS THE REGION DRY.
OVERNIGHT, THE WARM FRONT MOVES INTO N LOWER AND RAIN SHOWERS, AND
POSSIBLY THUNDERSTORMS WILL BREAK OUT.  SATURDAY, IT NOW LOOKS LIKE
THAT RAIN WILL CONTINUE ALONG THE WARM FRONT AS IT STALLS OVER THE
FORECAST AREA, BUT THERE WILL PROBABLY BE BREAKS. SUNDAY, NOT SURE
THAT I WOULD TRUST EITHER THE GFS OR THE ECMWF NOW. HOWEVER, SINCE
THEY ARE MUCH CLOSER TO EACH OTHER IN SOLUTION, WILL GO WITH THE
RAIN SHOWER/THUNDERSTORM CHANCES AS THE SFC LOW MOVES UP THE
MISSISSIPPI VALLEY. MONDAY, THE RAIN CONTINUES AS THE SFC LOW AND
THE 500 MB LOW STACK UP AND MOVE INTO THE UPPER GREAT LAKES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1148 PM EDT MON MAY 13 2013

TOP-DOWN SATURATION WILL CONTINUE AHEAD OF APPROACHING
ELEVATED WARM FRONT. SPRINKLES/LIGHT RAIN MAY SPREAD ACROSS THE TAF
SITES THROUGH THE EARLY MORNING...ALTHOUGH DEARTH OF LOW LEVEL
MOISTURE LIKELY TO KEEP CONDITIONS VFR. FORCING MOVES EAST LATER
TUESDAY...ENDING THE RAIN THREAT.

ATTENDANT LOW LEVEL JET WILL DEVELOP WIND SHEAR ACROSS WESTERN TAF
SITES LATE THROUGH THE MID MORNING HOURS.


&&

.MARINE...
ISSUED AT 326 PM EDT MON MAY 13 2013

HIGH PRESSURE WILL BUILD ACROSS THE WATERS THIS EVENING WITH MUCH
LIGHTER WEST TO NORTHWEST WINDS...PERHAPS UP TO 15 KNOTS IN SPOTS
AT TIMES. A PERIOD OF STRONGER WINDS MAY ARRIVE FOR PARTS OF LAKE
MICHIGAN OVERNIGHT AS A SURGE OF WARMER AIR RIDES IN ALOFT...BUT
RATHER NEUTRAL OVER-WATER THERMAL PROFILES SUGGEST CONDITIONS
SHOULD REMAIN BELOW SMALL CRAFT ADVISORY LEVELS. LOOKING INTO
MIDWEEK...A COLD FRONT WILL CROSS THE WATERS SOMETIME TUESDAY
NIGHT...WITH ANOTHER PERIOD OF STRONGER WINDS POSSIBLE BOTH AHEAD
OF AND BEHIND THAT FEATURE...BEFORE LIGHTER WINDS MAKE A RETURN BY
LATE WEEK AS HIGH PRESSURE BUILDS BACK ACROSS THE AREA.


&&

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

&&

$$

UPDATE...SD
SYNOPSIS...KB
SHORT TERM...JK
LONG TERM...JL
AVIATION...MB
MARINE...JK