639  
FXUS63 KDTX 250733  
AFDDTX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI  
333 AM EDT WED MAY 25 2016  
   
DISCUSSION
 
 
APPEARS IN THE LONG RANGE MODELS THAT THE CURRENT WESTERN CONUS  
TROUGH AND EASTERN CONUS RIDGE WILL HOLD THROUGH THE NEXT WEEK OR  
MORE. THIS MEANS THE CURRENT WARM AIRMASS WILL HOLD IN PLACE WITH  
HIGH TEMPERATURES LARGELY IN THE 80S THROUGH THE FORECAST. IT ALSO  
MEANS THE NORTHEAST FLOW REGIME WILL PERSIST WITH A SERIES OF  
SHORTWAVES EJECTING OUT OF THE TROUGH UP THROUGH THE MIDWEST KEEPING  
CHANCES OF THUNDERSTORMS IN THE FORECAST NEARLY EVERY DAY. IT WON'T  
BE A COMPLETE WASH OUT THIS WEEK THOUGH AS BEST CHANCES OF  
PRECIPITATION WILL BE TIED TO SHORTWAVES WITH AN OVERALL LACK OF  
LOWER LEVEL LIFTING MECHANISMS. ONE OTHER THING TO WATCH FOR WILL BE  
UPSTREAM MCS'S AND THE POTENTIAL THEY CAN HOLD TOGETHER INTO LOWER  
MICHIGAN.  
 
CURRENTLY THERE IS A STALLED COLD FRONT DRAPED ACROSS MID MICHIGAN  
WHICH WAS THE FOCUS FOR SOME SHOWERS AND THUNDERSTORMS ON TUESDAY  
AND TUESDAY NIGHT. A NARROW RIBBON OF ENHANCED THETA E WAS CO-  
LOCATED ALONG THE FRONT PROVIDING A BOOST IN MOISTURE TO A  
RELATIVELY DRY COLUMN, WHILE WEAK CONVERGENCE DEVELOPED AT THE  
SURFACE AT THE FRONT. A FAIRLY STRONG MID LEVEL SHORT WAVE HAS  
LIFTED OUT OF SOUTHERN CALIFORNIA AND WILL PASS THROUGH MN AND INTO  
ONTARIO THIS EVENING. A LOBE OF VORTICITY EXTENDING SOUTHEAST FROM  
THE DEVELOPING MID LEVEL LOW WILL SWEEP THROUGH SOUTHERN MICHIGAN  
THIS EVENING, WHICH WILL CHANGE THE STALLED FRONT INTO A WARM FRONT  
THAT WILL LIFT NORTH TOWARD THE STRAITS BY EARLY THURSDAY AFTERNOON.  
THIS WILL PRESENT ONE OF THE BEST OPPORTUNITIES FOR THUNDERSTORMS IN  
THE FORECAST AS THE NOSE OF A STRONG THETA E SURGE LIFTS INTO THE  
AREA BEHIND THE WARM FRONT. ELEVATED LEVELS OF CAPE AROUND 500-1000  
J/KG, SHEAR INCREASING TO AROUND 30 KNOTS, AND FAVORABLE MID LEVEL  
LAPSE RATES AND LI'S WILL ALSO ACCOMPANY THE FRONT. SOME STORMS  
COULD BECOME STRONG BUT STABILITY IN THE LOWER LEVELS WILL KEEP  
THINGS MORE ELEVATED WHICH COULD REDUCE GUST POTENTIAL. COVERAGE  
SHOULD INCREASE OVER THE WESTERN AND NORTHERN PART OF THE SE MI BUT  
MOST LOCATIONS WILL HAVE AT LEAST A HIGH CHANCE OF SHOWERS.  
 
ANOTHER WAVE IS SET EJECT THROUGH THE FLOW FRIDAY MORNING PRESENTING  
THE NEXT GOOD CHANCE AT WIDESPREAD SHOWERS AND THUNDERSTORMS ACROSS  
THE AREA. UPSTREAM TROUGH AMPLIFICATION WILL LEAD TO THE RESIDENT  
RIDGE GETTING PULLED BACK TO THE WEST WHICH WILL PULL THE BETTER  
SUPPORT WESTWARD AS WELL. WILL HAVE TO WATCH HOW THIS ALL EVOLVES  
MOVING FORWARD AS LARGE CONVECTIVE SYSTEMS IN THE PLAINS MAY KEEP  
THE LOWER HEIGHTS FURTHER SOUTH AND EAST.  
 
HEADING INTO THE WEEKEND THE WAVE TRAIN CONTINUES BUT TIMING ANY OF  
THESE FEATURES IS DIFFICULT AT BEST WITH THIS TYPE OF ACTIVE  
PATTERN. IT IS WORTH NOTING THAT OUTSIDE OF THE TWO MORE DOMINATE  
WAVES HEADING INTO THE WEEKEND, THE MODELS ARE ALL FAIRLY UNIFORM IN  
PRESENTING MORE OF A DIURNAL COMPONENT TO THE SHOWER ACTIVITY. ONCE  
WE GET THE HIGHER DEW POINTS INTO THE REGION, A SUMMER LIKE PATTERN  
WILL ENSUE WITH DIURNAL HEATING POPPING A FEW SHOWERS IN THE  
AFTERNOON. WITH LACK OF ANY FOCUSING MECHANISM COVERAGE WILL BE ILL  
DEFINED, HENCE A DAILY CHANCE POP LINGERS IN THE FORECAST.  
 

 
   
MARINE
 
 
A WEAK COLD FRONT WILL REMAIN THE FOCAL POINT FOR MARINE WEATHER IN  
THE SHORT TERM AS IT SETTLES INTO SOUTHERN LAKE HURON AND CENTRAL  
LOWER MICHIGAN TODAY AND THEN RETURNS NORTHWARD TONIGHT. THE WIND  
WILL BE LIGHT WITHIN AND AROUND THE FRONTAL ZONE LEAVING THE MAIN  
IMPACT TO BE SHOWERS AND THUNDERSTORMS THAT WILL BECOME MORE  
NUMEROUS TONIGHT. FOG WILL ALSO BECOME INCREASINGLY PREVALENT AS THE  
WARM AND HUMID AIR POOLS OVER THE COLDER OPEN WATERS OF LAKE HURON.  
 
THE FRONT WILL MOVE NORTHWARD INTO CANADA THURSDAY AND LEAVE LIGHT  
SOUTHERLY WIND OVER ALL MARINE AREAS THAT WILL MAINTAIN WARM AIR  
FRIDAY INTO SATURDAY. SHOWERS AND STORMS REMAIN POSSIBLE BUT WILL BE  
LESS ORGANIZED UNTIL POSSIBLY LATER SATURDAY AND SATURDAY NIGHT AS  
LOW PRESSURE DEVELOPS OVER THE UPPER MIDWEST. THIS SYSTEM WILL ALSO  
HELP MAINTAIN WARM CONDITIONS AND LIGHT SOUTH WIND WELL INTO THE  
HOLIDAY WEEKEND.  
 

 
   
HYDROLOGY
 
 
WARM AIR WITH INCREASING HUMIDITY WILL POOL ALONG A FRONT SETTLING  
AS FAR SOUTH AS THE I-69 CORRIDOR TODAY. HIGH TEMPERATURES RETURNING  
TO THE LOWER AND MID 80S COULD RESULT IN A FEW THUNDERSTORMS ALONG  
THE FRONT DURING THE AFTERNOON AND EVENING. SHOWERS AND STORMS ARE  
THEN EXPECTED TO INCREASE COVERAGE OVERNIGHT WITH THE HELP OF LOW  
PRESSURE OVER THE MIDWEST THAT WILL PULL THE FRONT NORTHWARD  
THURSDAY. RAINFALL AMOUNTS ARE EXPECTED TO VARY WIDELY DEPENDING ON  
THUNDERSTORM COVERAGE BUT SHOULD AVERAGE 0.25 TO 0.5 INCH FOR THE  
WEDNESDAY NIGHT-THURSDAY PERIOD WITH LOCALLY HIGHER TOTALS NEAR 1  
INCH POSSIBLE IN THUNDERSTORMS. WARM AND HUMID AIR WILL THEN REMAIN  
IN PLACE TO SUPPORT SHOWER AND THUNDERSTORM POTENTIAL INTO THE  
WEEKEND WITH LESS ORGANIZATION UNTIL ARRIVAL OF THE NEXT LOW  
PRESSURE SYSTEM POSSIBLY BY SATURDAY INTO SATURDAY NIGHT.  
 

 
   
PREV DISCUSSION
 
 
ISSUED AT 1155 PM EDT TUE MAY 24 2016  
 
AVIATION...  
 
PERSISTENTLY DRY/STABLE LOW LEVEL ENVIRONMENT WILL SUSTAIN A CLEAR  
SKY WITHIN THE LOWEST 5000 FT TONIGHT AND EARLY WEDNESDAY. MODEST  
SOUTHWESTERLY FLOW DURING THIS TIME AS DOMINANT HIGH PRESSURE OF  
RECENT DAYS GRADUALLY PULLS EAST. WEAKENING FRONTAL BOUNDARY WILL  
SLIDE INTO CENTRAL LOWER MI DURING THE EARLY MORNING PERIOD. THIS  
MAY SUPPORT SOME WIDELY SCATTERED HIGH BASED SHOWERS IN THE VICINITY  
OF MBS. GRADUAL INCREASE IN MOISTURE WEDNESDAY MAY ALLOW FOR A LOW  
COVERAGE OF LATE DAY VFR CUMULUS. PROSPECTS FOR THUNDERSTORM  
DEVELOPMENT THROUGH WEDNESDAY EVENING REMAIN TOO LOW TO INCLUDE AT  
THIS TIME.  
 
//DTW THRESHOLD PROBABILITIES...  
 
* NONE  
 

 
   
DTX WATCHES/WARNINGS/ADVISORIES
 
 
MI...NONE.  
LAKE HURON...NONE.  
LAKE ST CLAIR...NONE.  
MICHIGAN WATERS OF LAKE ERIE...NONE.  

 
 

 
 
DISCUSSION...DRK  
MARINE.......BT  
HYDROLOGY....BT  
AVIATION.....MR  
 
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE  
AT WWW.WEATHER.GOV/DETROIT.  
 
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