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000
FXUS63 KMQT 141026
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
626 AM EDT TUE MAY 14 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 625 AM EDT TUE MAY 14 2013

UPPER PATTERN IN PROCESS OF BECOMING MORE ZONAL. NOT QUITE THERE YET
ACROSS UPPER LAKES THOUGH AS DEEP TROUGH OVER EASTERN CANADA STILL
IS CLOSE BY. SWATH OF MID CLOUDS AND SCATTERED SHOWERS SUPPORTED BY
H7 MOISTURE ADVECTION AND H85 WARM AIR ADVECTION IS ARE SLIDING
ACROSS MAINLY EAST CWA. CLOUDS HAVE ALREADY CLEARED WEST THIRD OF
CWA. RAIN AMOUNTS OVR CNTRL CWA MAYBE A COUPLE HUNDREDTHS...BUT FIRE
WX OBS ON MESOWEST SHOW MORE WIDESPREAD 0.02-0.05 INCH AMOUNTS OVER
EASTERN CWA WHERE ANOTHER HOUR OR TWO OF SHOWERS ARE POSSIBLE. RAIN
MOVES OUT BY DAYBREAK. BRIEF CLEARING EARLY ON...THEN EXPECT MID TO
HIGH CLOUDS /H6-H5 RH/ TO INCREASE BY LATE MORNING OVER WESTERN CWA
AND SPREAD ACROSS REST OF CWA THIS AFTN. CLOUDS ARE THANKS TO
BLOWOFF FROM CONVECTIVE COMPLEX MOVING OVR CNTRL ND. WELL MIXED BLYR
UP TO H5 IS SUPPORTING WIND GUSTS 40-60 KTS OVR ND THIS MORNING.
COMPLEX IS A BIT OUT AHEAD OF PRIMARY SHORTWAVE/PV ANOMALY AND IS
MORE ON EDGE OF H5 JET OF 70+ KTS. H7-H5 LAPSE RATES OVER 8.5C/KM
RESULTING IN MUCAPES UP TO 1000J/KG LEADING TO DECENT COVERAGE TO
LIGHTNING OVR ND.

THINKING THAT MAIN CONCERN THROUGH TODAY IS FATE OF CONVECTIVE
COMPLEX OVR ND. COMPLEX SHOULD WEAKEN AS IT HEADS INTO NORTHERN
MINNESOTA AS IT OUTRUNS BETTER INSTABILITY OVER NORTHERN PLAINS.
YET...SINCE IT IS SUPPORTED BY H5 JET AND SUBTLE H7-H3 PVA AHEAD OF
PRIMARY SHORTWAVE...THINK IT HAS AN OKAY SHOT AT REACHING WESTERN
CWA BY EARLY THIS AFTN PER DISTANCE TIME TRACKING TOOL. PREVIOUS
FORECAST HAD SMALLISH POPS OVR NW CWA THIS AFTN SPREADING TO REST OF
CWA BY EVENING. THINKING THIS IS ON TRACK AND GENERALLY KEPT THAT
IDEA. BASED ON 1-6KM MUCAPE AND H7-H5 LAPSE RATES...THINKING IS
THERE WILL BE LIMITED CHANCES OF THUNDER UNTIL LATE IN THE AFTN OVER
THE FAR WEST. BLOWOFF CLOUDS/ISOLD SHRA PUSHING INTO CWA ALONG WITH
SHALLOW MIXED LAYER BENEATH BROAD SCALE WARM ADVECTION SHOULD KEEP
TEMPS FROM GETTING TOO WARM TODAY. SOME GUIDANCE INDICATED UPPER 70S
TO NEAR 80 IN THE FAR WEST. GIVEN CLOUD SITUATION...STUCK MORE WITH
PREVIOUS FCST BLENDED WITH ECMWF/GFS MOS. RESULT WAS LOWER 70S WEST
AND SOUTHWEST...WITH MAINLY 60S ELSEWHERE...EXCEPT ALONG IMMEDIATE
GREAT LAKES SHORES WHERE 50S WILL BE MORE COMMON WITH OVERALL SE
FLOW.

FORECAST FOR TONIGHT STILL LOOKS TRICKY. GLANCING THROUGH VARIOUS
MODEL SOLUTIONS THEY ALL APPEAR IN GENERAL AGREEMENT THAT BEST
CHANCE FOR SHRA/TSRA WOULD BE THIS EVENING WITH SHARP DRYING TREND
DEVELOPING OVERNIGHT DUE TO H7-H5 WARMING AND DRYING WITH DWPNT
DEPRESSIONS INCREASING ABOVE 20C. EXTENT OF SHRA/TSRA THIS EVENING
IS MAIN STICKING POINT. SOUNDINGS POINT TO AN INITIAL DRY AIRMASS
THOUGH WITH THE CONVECTIVE COMPLEX PUSHING ACROSS LK SUPERIOR COULD
IMPACT THIS. MOISTURE ADVECTION H9-H8 THEN OCCURS AHEAD OF COLD
FRONT. LIFTING FROM H8 RESULTS IN OVER 1000J/KG OF MUCAPE WITH AT
LEAST A PORTION OF THIS OCCURRING IN THE HAIL GROWTH LAYER. TROUBLE
IS THAT IF LIFTING TAKES PLACE MORE IN THE SUB H8 LEVEL...THERE
WOULD LIKELY BE TOO MUCH CINH TO OVERCOME. EVEN IF A PARCEL IS
LIFTED FROM H8 THE EFFECTIVE SHEAR IS ONLY AROUND 20-30 KTS SO THAT
IS MARGINAL FOR STORM ORGANIZATION. RISK FOR SEVERE IS STILL THERE
BUT AS IT HAS LOOKED FOR LAST FEW DAYS...IT IS MARGINAL AT BEST.
WITH SUCH STRONG WINDS H7-H3...35KT AT H7 TO 65KT AT H5...IF ENOUGH
MOISTURE IS NOT PRESENT THEN DRY AIR ENTRAINMENT COULD WRECK
CONVECTIVE DEVELOPMENT. THIS MAY BE WHAT SOME OF THE DRIER MODELS
ARE HINTING AT IN THEIR QPF FIELDS. OVERALL...PREVIOUS FCST SHOWS
EXPECTED TRENDS WELL AND DID NOT ALTER IT TOO MUCH.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 625 AM EDT TUE MAY 14 2013

MODEL SNDGS SHOW GOOD MID-LVL DRYING/SUBSIDENCE IN THE WAKE OF THE
COLD FRONT AS 8H TEMPS DROP TO 8-9C. MODELS INDICATE PW VALUES DROP
BLO .5 INCH OR OR 60-70 PERCENT OF NORMAL. GFE MIXED DEWPOINT TOOL
FOR THE NAM AND GFS SHOWS POTENTIAL FOR DEWPOINTS TO DROP INTO THE
LOWER TO MID 20S OVER THE WRN INTERIOR. LOOKING AT HOW DRY MODEL
SNDGS ARE ABV 825 MB THESE DEWPOINTS WOULD NOT BE FAR-FETCHED AT
ALL...ESPECIALLY IF WE MIX NEAR 800 MB. WITH T/TD OF 74/24 MIN RH
VALUES WOULD DROP NEAR 15 PERCENT. NW WIND SHOULD STAY JUST BLO RED
FLAG CRITERIA WITH SUSTAINED WINDS AROUND 15 KT AND GUSTS AROUND 20
KT. HOWEVER IF PCPN IS LIMITED TUE NIGHT...FIRE DANGER WILL
DEFINITELY BE A CONCERN FOR WEDNESDAY. DAY SHIFT MAY NEED TO
COORDINATE WITH FIRE WX USERS TODAY TO SEE IF FIRE WEATHER WATCH MAY
BE NEEDED FOR WED AFTERNOON.

MODELS SHOW A TROUGH MOVING THROUGH THE AREA WED NIGHT BUT NO PCPN
IS EXPECTED FM THIS FEATURE AS THE AIRMASS AND FCST WILL REMAIN DRY
INTO FRI MORNING UNDER CONFLUENT FLOW ALOFT AND BUILDING 5H RDG
HEIGHTS.  EXPECT THE SURFACE RIDGE OF HIGH PRESSURE TO BE DIRECTLY
OVERHEAD ON THURSDAY WHICH WILL RESULT IN LIGHT WINDS AND LAKE
BREEZES CIRCULATIONS.

INCREASING WAA/ISENTROPIC LIFT FRI AFTERNOON INTO SAT MORNING
SPREADING FM WEST TO EAST ACROSS THE CWA WILL BRING AN INCREASED CHC
OF SHOWERS FRI NIGHT INTO SATURDAY MORNING FOR MUCH OF THE CWA. FCST
SHOWALTER INDICES AND MUCAPE VALUES INDICATE CHC OF THUNDERSTORMS
DURING THIS TIME WILL BE MAINLY CONFINED TO THE WEST HALF OF THE CWA
LATE FRI NIGHT INTO SAT MORNING. AS 850 MB WARM FRONT LIFTS NORTH OF
THE CWA BY SATURDAY AFTERNOON...MODEL SNDGS SUGGEST ENVIRONMENT WILL
BECOME CAPPED BY WARMER/DRIER AIR AND THUS EXPECT A LULL IN SHOWER
ACTIVITY FOR SAT AFTERNOON INTO AT LEAST SAT EVENING.

BOTH THE 00Z ECMWF AND GFS INDICATE A SHORTWAVE LIFTING OUT FM BASE
OF UPR TROUGH OVER THE SRN PLAINS AND TOWARD THE UPPER MS VALLEY ON
SUNDAY. THIS SHORTWAVE WILL HELP PUSH FRONTAL BOUNDARY CLOSER TO THE
UPPER MS VALLEY AND OUR WRN CWA ESPECIALLY SUN AFTERNOON. 8H THETA-E
MAXIMUM ALONG THE FRONTAL BOUNDARY AND CORRESPONDING INCREASE IN
INSTABILITY (MLCAPES REACH 700-1200 J/KG OVER WEST HALF) WILL
WARRANT AN INCREASED CHC OF SHRA AND TSRA FOR SUNDAY ESPECIALLY OVER
THE WEST HALF. WILL MAINTAIN HIGH CHC POPS FOR SHRA/TSRA SUN NIGHT
INTO MONDAY ACROSS THE CWA AS MAIN SHORTWAVE AND ASSOC COLD FRONT
MOVE ACROSS THE UPPER GREAT LAKES.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 139 AM EDT TUE MAY 14 2013

VFR CONDITIONS REMAIN THE RULE AT ALL THREE TAF SITES THROUGH THE
FORECAST PERIOD. CLOUD COVER AND RAIN SHOWERS HAVE ALL BUT EXITED
KIWD AREA AND WILL MOVE OUT OF KCMX BY 8Z...AND KSAW SHORTLY AFTER
THEN. WEAK RIDGING ALOFT BEHIND THE DISTURBANCE WILL REDUCE CLOUD
COVER UNTIL THE APPROACH OF THE NEXT SHORT WAVE BRINGS INCREASING MID
AND HIGH CLOUDS TO THE AREA IN THE LATE AFTERNOON/EVENING. AT THIS
TIME...BETTER MOISTURE AND LOW LEVEL FORCING TO BE FOUND SOUTH OF THE
AREA IN WI...WHILE BETTER DYNAMIC LIFT LOCATED NORTH OF THE
BORDER...LEAVING THE THREE TAF SITES IN BETWEEN. WITH NO STRONG
SIGNAL...WILL JUST MENTION VCSH AT KIWD AND KCMX AND WILL LEAVE OUT
OF KSAW FOR NOW.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 625 AM EDT TUE MAY 14 2013

INCREASING SOUTHERLY FLOW OCCURRING AHEAD OF A LOW PRESSURE SYSTEM
MOVING EAST THROUGH SOUTHERN CANADA. INCREASING WARM AIR ABOVE THE
SURFACE SHOULD LIMIT GUSTS TO 20KTS IN MOST LOCATIONS TODAY. WINDS
INCREASE TO 25 KTS TONIGHT AND STILL MAY REACH 30 KTS IN THE
WESTERLY FLOW ON WEDNESDAY BEHIND COLD FRONT MOVING THROUGH LATE
TONIGHT. WINDS ARE EXPECTED TO REMAIN BELOW 30KTS LATER THIS WEEK
AND INTO THE WEEKEND. AFTER COOL AND WINTRY WEATHER FOR THE SPRING
SO FAR...SUMMERTIME WEATHER IS BECOMING MORE COMMON. THUNDERSTORMS
ARE POSSIBLE LATE THIS AFTERNOON OVER WESTERN LAKE
SUPERIOR...PUSHING EASTWARD OVERNIGHT TONIGHT AND ENDING BY EARLY
WEDNESDAY. ANOTHER ROUND OF THUNDERSTORMS WILL BE POSSIBLE WEST ON
SATURDAY/SATURDAY NIGHT...AND ACROSS ALL OF LAKE SUPERIOR SUNDAY
THROUGH MONDAY MORNING.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...JLA
LONG TERM...VOSS
AVIATION...RJT
MARINE...JLA