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000
FXUS63 KDTX 130349
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1149 PM EDT SUN MAY 12 2013


.AVIATION...

//DISCUSSION...

HIGH PRESSURE BUILDING INTO THE REGION WILL PROVIDE MOSTLY CLEAR
SKIES AND LIGHT WINDS THROUGH MONDAY MORNING. THE RIDGE ITSELF WILL
TRACK THROUGH THE CENTRAL GREAT LAKES ON MONDAY. WIND GUSTS WILL
PICK BACK UP TO 10 TO 15 KNOTS DURING THE DAY ON MONDAY WITH DAYTIME
HEATING ALONG WITH SOME DIURNAL CUMULUS CLOUDS. HOWEVER WITH WARMER
AIR BUILDING IN AND SUBSIDENCE ASSOCIATED WITH THE RIDGE COVERAGE IS
EXPECTED TO BE SCATTERED. A WEAK LOW PRESSURE SYSTEM TRACKING
THROUGH THE REGION MONDAY NIGHT WILL BRING THICKENING MID LEVEL
CLOUDS TO THE TAF SITES.

//DTW THRESHOLD THREATS...

* NONE.

&&

.PREV DISCUSSION...ISSUED 1005 PM EDT SUN MAY 12 2013

UPDATE...

GALES HAVE SUBSIDED THIS EVENING...HOWEVER GUSTY WINDS AND HIGH
WAVES CONTINUE FOR MANY OF THE NEARSHORE AREAS. GALES HAVE BEEN
REPLACED BY SMALL CRAFTS ACROSS SAGINAW BAY AND LAKE HURON FROM
PORT AUSTIN TO HARBOR BEACH. FARTHER SOUTH OVER LAKE ST. CLAIR AND
WESTERN LAKE ERIE WINDS HAVE FALLEN BELOW CRITERIA...WITH
HEADLINES EXPIRING ON TIME. THE REST OF THE HEADLINES ARE
UNTOUCHED. HIGH PRESSURE THEN REMAINS READY TO BUILD INTO THE
AREA MONDAY FOR MUCH IMPROVED MARINE CONDITIONS THROUGH MONDAY
NIGHT. THE NEXT CHANCE OF UNSETTLED WEATHER IS EXPECTED TUESDAY AS
A WARM FRONT APPROACHES THE GREAT LAKES.

PREV DISCUSSION...ISSUED 354 PM EDT SUN MAY 12 2013

SHORT TERM... LATE AFTERNOON AND TONIGHT

GUSTY NORTHWEST WIND AND SCATTERED LIGHT RAIN SHOWERS WILL DIMINISH
WITH THE LOSS OF SURFACE HEATING TOWARD SUNSET. RADAR INDICATES THE
PEAKING DIURNAL CYCLE IS ALREADY SHOWING SIGNS OF STRUGGLE TO
SUPPORT SHOWER ACTIVITY. MODEL ANALYSIS FIELDS INDICATE THIS IS DUE
PRIMARILY TO THE LOWER THETA-E CHARACTER OF THE LOW LEVEL THERMAL
TROUGH SETTLING OVER THE REGION. EXPECT NO MORE THAN SCATTERED
COVERAGE OF WEAKER CONVECTION COMPARED TO EARLY AFTERNOON ACTIVITY
THAT WAS ABLE TO PRODUCE SMALL GRAUPEL AS FAR SOUTH AS OAKLAND
COUNTY.

THE FREEZE WARNING REMAINS IN EFFECT TONIGHT AS CLEARING SKY AND
DIMINISHING WIND ADDS A RADIATIONAL COOLING COMPONENT TO THE ALREADY
NEAR RECORD COLD AIR MASS. THE ABOVE MENTIONED DRYING TREND IN
SHOWER ACTIVITY, ALONG WITH THE SATELLITE TREND OVER THE WESTERN
GREAT LAKES, LENDS CONFIDENCE TO THE DIMINISHING CLOUD EXPECTATIONS,
ESPECIALLY AFTER MIDNIGHT. SOME PATCHES OF STRATOCU WILL LINGER INTO
THE EVENING AS THE DIURNAL COMPONENT OF COVERAGE FADES AROUND AND
WITHIN ANY LINGERING STRATIFIED MOISTURE. THERE IS ALSO THE PROSPECT
OF SOME MID TO HIGH CLOUDS BRUSHING THE THUMB DUE TO MOISTURE
WRAPPING AROUND THE SOUTHWEST FLANK OF THE LOW NOW OVER NORTHERN
QUEBEC BUT MOVING AWAY. THE MAIN QUESTION WILL BE HOW MUCH THE
LINGERING WEAK PRESSURE GRADIENT CAN STAND UP TO DECOUPLING UNDER
CLEAR SKY BY SUNRISE MONDAY. THE FORECAST MIN GRID IS SET UP ON THE
COLD END OF THE GUIDANCE SPECTRUM IN THE LOWER 30S NEAR THE
SHORELINES AND IN THE DETROIT METRO AREA TO UPPER 20S INTERIOR. HERE
ARE THE RECORD LOWS FOR MAY 13TH AS COMPILED BY THE MORNING CREW.

MBS...26 (1946)
FNT...28 (1946)
DTW...30 (1971)

LONG TERM...MONDAY THROUGH SATURDAY

DEEP MID LEVEL TROUGH WILL BE DEPARTING EASTWARD OUT OF THE GREAT
LAKES ON MONDAY AS THE WEST COAST RIDGE APPROACHES. A WEAK SHORTWAVE
WORKING UP AND OVER THE RIDGE WILL BEGIN SUPPRESSING THE RIDGE
BEFORE A STRONGER WAVE BARRELS INTO IT LATE MONDAY FLATTENING IT OUT
AND PRODUCING NEARLY ZONAL FLOW ACROSS THE NORTHERN CONUS THROUGH
THE REMAINDER OF THE WORK WEEK. WITH THE JET STREAM TO OUR
NORTH...INCREASING HEIGHTS AND WESTERLY FLOW WILL ALLOW TEMPS TO
RECOVER BACK TO JUST ABOVE NORMAL FOR THE WEEK. EARLY WEEK WARM
FRONT LIFTING THROUGH THE AREA WILL USHER IN A WARM MOIST AIRMASS
AND CHANCES OF THUNDERSTORMS AND A SERIES OF WEAK COLD FRONTS
DROPPING INTO AND NEAR SE MI WILL KEEP CHANCES AROUND THROUGH THE
END OF THE WEEK.

THE MAIN SYSTEM WE WILL BE WATCHING WILL BE A STRENGTHENING LOW
TRACKING ACROSS SOUTHERN CANADA TUESDAY THROUGH THURSDAY. THIS WILL
LIFT A WARM FRONT NE THROUGH MI ON THE FORWARD FLANK OF THE BUILDING
MIDLEVEL RIDGE ON TUESDAY. STRONG WAA ADVECTION WILL COMMENCE AS
STIFF SOUTHWESTERLY FLOW INCREASES 850MB TEMPS BY 15C FROM 12Z
TUESDAY TO 12Z WEDNESDAY. IN ADDITION...MID LEVEL RIDGE AXIS WILL
TRAVERSE THE REGION DURING PEAK HEATING WITH THE INCREASING SW FLOW.
THIS WILL LEAD TO A VERY WARM DAY WEDNESDAY WITH MAX T/S AROUND 80F.
THE SYSTEM WILL THEN PULL A COLD FRONT THROUGH THE STATE WEDNESDAY
AFTERNOON. TIGHT THETA E GRADIENT ALONG THE FRONT...CAPE VALUES IN
EXCESS OF 1500 J/KG...STRONG MID LEVEL LAPSE RATES...SHOWALTER
VALUES NEAR -3...ALL SUGGEST THUNDERSTORMS IN THE WARM SECTOR AND
ALONG THE FRONT. ONE THING TO KEEP IN MIND IS THE STRONG
CAP/INVERSION BETWEEN 850-800 MB. MODEL SOUNDINGS SUGGEST A PERIOD
OF ELEVATED CONVECTION BEFORE DAYTIME HEATING HAS A CHANCE TO BREAK
THE CAP ALLOWING MORE SURFACE BASED CONVECTION. WILL BE SOMETHING TO
KEEP AN EYE ON FOR SURE.

THE END OF THE WEEK BECOMES A BIT MORE GENERIC. THE COLD FRONT
BECOMES DRAPED E/W ACROSS THE OHIO VALLEY. MODELS HAVE BEEN
FLUCTUATING NORTH AND SOUTH WITH WHERE THE FRONT WILL SETTLE WHICH
WILL DETERMINE WHERE SHOWERS/THUNDERSTORMS WILL BE MORE PREVALENT.
HAVE KEPT HIGHER POPS ACROSS THE FAR SOUTH FOR MOST PERIODS TO
ACCOUNT FOR THIS. SEVERAL OTHER WEAK FRONTS WILL ATTEMPT TO DROP
THROUGH NORTHERN MI AS SYSTEMS SHOOT ACROSS CANADA IN THE ZONAL FLOW
WHICH WILL PRESENT ADDITIONAL CHANCES FOR SHOWERS FROM THE NORTH. IN
ADDITION...THERE WILL LIKELY BE A VORT MAX OR TWO EMBEDDED IN THE
ZONAL FLOW PASSING THROUGH MI BUT THESE WILL BE ADDRESSED WITH A
SHORTER FUSE AS THEY BECOME MORE EVIDENT.

MARINE...

GALE WARNINGS ARE EXTENDED THROUGH THE EVENING AS SURFACE REPORTS
CONTINUE TO SHOW SOLID GALE POTENTIAL. THE SMALL CRAFT ADVISORY IS
EXTENDED THROUGH MONDAY MORNING FOR LINGERING WAVE ACTION. FARTHER
SOUTH THROUGH LAKE ST CLAIR AND WESTERN LAKE ERIE, WESTERLY WINDS
WILL CONTINUE GUSTING TO 30 KNOTS THROUGH THE EVENING AS WELL. HIGH
PRESSURE THEN REMAINS READY TO BUILD INTO THE AREA MONDAY FOR MUCH
IMPROVED MARINE CONDITIONS THROUGH MONDAY NIGHT. THE NEXT CHANCE OF
UNSETTLED WEATHER IS EXPECTED TUESDAY AS A WARM FRONT APPROACHES THE
GREAT LAKES.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...FREEZE WARNING...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055-MIZ060-
     MIZ061-MIZ062-MIZ063-MIZ068-MIZ069-MIZ070-MIZ075-MIZ076-MIZ082-
     MIZ083...UNTIL 8 AM MONDAY.

LAKE HURON...
     SMALL CRAFT ADVISORY...SAGINAW BAY...UNTIL 4 AM MONDAY.

     SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO PORT
     HURON...UNTIL 10 AM MONDAY.

LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.

&&

$$

AVIATION.....KURIMSKI
UPDATE.......KURIMSKI
SHORT TERM...BT
LONG TERM....DRK
MARINE.......BT


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