816  
FXUS63 KAPX 220113  
AFDAPX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GAYLORD MI  
913 PM EDT TUE MAY 21 2019  
   
UPDATE
 
 
ISSUED AT 913 PM EDT TUE MAY 21 2019  
 
POWERFUL LOW PRESSURE REMAINS CENTERED OVER KANSAS LATE THIS  
EVENING...WITH THE ASSOCIATED WARM FRONT EXTENDING EASTWARD THRU  
CENTRAL MISSOURI TO JUST SOUTH OF THE OHIO VALLEY. LINE OF SEVERE  
STORMS CONTINUES TO IMPACT THE MID MISSISSIPPI VALLEY...PRODUCING  
A VARIETY OF SEVERE WX AS WELL AS FLOODING. CLOSER TO HOME...MID  
AND HIGH CLOUDS CONTINUE TO INCREASE ACROSS OUR CWA ALONG THE FAR  
NE PERIPHERY OF THE MOISTURE SHIELD ASSOCIATED WITH THIS SYSTEM.  
CLOSEST PRECIP THAT IS ACTUALLY REACHING THE GROUND IS STILL WELL  
WEST OF OUR AREA OVER WESTERN WISCONSIN WHERE SOME SHOWERS ARE  
OCCURRING. NEAR TERM MODELS ARE STILL KEEPING ANY PRECIP CHANCES  
AT BAY UNTIL 06Z. CHANCES OF RAIN WILL STEADILY INCREASE FROM SW  
TO NE ACROSS MUCH OF OUR CWA BETWEEN 06Z AND 12Z. GOING FORECAST  
IS IN LINE WITH LATEST MODEL AND OBSERVED DATA...SO NO MAJOR  
CHANGES NEEDED AT THIS TIME. STILL DO NOT EXPECT ANY CHANCE OF  
THUNDER OVERNIGHT DUE TO LACK OF INSTABILITY.  
 

 
   
NEAR TERM
 
(THROUGH TONIGHT)  
ISSUED AT 320 PM EDT TUE MAY 21 2019  
   
..INCREASING CLOUDS AND SHOWER CHANCES
 
 
HIGH IMPACT WEATHER POTENTIAL...NONE EXPECTED.  
 
PRIMARY FORECAST CONCERNS...TIMING OF SHOWER CHANCES.  
 
HIGH PRESSURE OVER THE REGION AT THE MOMENT WILL EXIT OFF TO OUR  
TONIGHT. ATTENTION WILL THEN TURN TO AN UPPER LEVEL TROUGH TRACKING  
OUT OF THE CENTRAL PLAINS. THIS SYSTEM WILL LEAD TO DOWNSTREAM  
ISENTROPIC ASCENT (I-310K)/WARM ADVECTION ACROSS NORTHERN MICHIGAN.  
RAIN SHOWERS WILL LIKELY OVERSPREAD THE REGION LATER TONIGHT FROM  
SOUTHWEST TO NORTHEAST. RAINFALL AMOUNTS WILL BE RATHER LIGHT WITH  
GENERALLY A TENTH OF AN INCH OR LESS. LOWS RANGING FROM THE LOWER  
40S ACROSS EASTERN UPPER TO THE UPPER 40S SOUTHWEST.  
 

 
   
SHORT TERM
 
(WEDNESDAY THROUGH FRIDAY)  
ISSUED AT 320 PM EDT TUE MAY 21 2019  
   
..SHOWER CHANCES RETURN
 
 
HIGH IMPACT WEATHER POTENTIAL: MINIMAL.  
 
PATTERN SYNOPSIS: ALL EYES CENTERED ON IMPRESSIVE TROUGH (ESPECIALLY  
FOR LATER MAY) ROTATING INTO THE CENTRAL PLAINS. TREMENDOUS GULF OF  
MEXICO MOISTURE INFLUX AND SIMPLE BREADTH OF DYNAMICS MORE THAN  
VERIFIED BY ONGOING SEVERE WEATHER AND EXTENSIVE FLOODING ACROSS  
LARGE PORTIONS OF MISSOURI, KANSAS, AND OKLAHOMA. WITH THAT SAID,  
SYSTEM HAS REACHED MATURITY, AND EXPECT ALL PHASES OF IT TO  
GRADUALLY WEAKEN AS IT PIVOTS NORTHEAST ACROSS THE UPPER MISSISSIPPI  
VALLEY REGION WEDNESDAY. ATTENDANT WARM FRONT AND DECAYING NORTHWARD  
SURGING MOISTURE CHANNEL BRINGS RENEWED RAIN CHANCES ACROSS OUR AREA  
LATER TONIGHT AND WEDNESDAY, WITH PASSAGE OF ACTUAL MID LEVEL  
WAVE/SURFACE LOW AND ITS ATTACHED COLD FRONT CONTINUING THE LIGHT  
SHOWER CHANCES WEDNESDAY NIGHT INTO THURSDAY. WESTERN CONUS REMAINS  
ENERGY FILLED THEREAFTER, SENDING ITS NEXT WAVE AND MORE SHOWER  
CHANCES INTO OUR AREA BY THE END OF THE WORK WEEK.  
 
PRIMARY FORECAST CONCERNS/CHALLENGES: TEMPERATURE TRENDS AND  
ADDRESSING BOTH SPATIAL AND TEMPORAL RESOLUTION OF SHOWERS.  
 
DETAILS: ISENTROPICALLY DRIVEN SHOWERS EXPECTED TO BE SPREADING  
SOUTHWEST TO NORTHEAST ACROSS THE AREA WEDNESDAY MORNING. AS  
MENTIONED EARLIER, DESPITE VERY IMPRESSIVE RAIN OCCURRING WITH THIS  
SYSTEM NOW, EXPECT NOTHING LIKE IT THIS FAR NORTH AS MOISTURE SURGE  
DECAYS AND OVERALL FORCING STRETCHES OUT/WEAKENS WITH TIME. ACTUAL  
BAND OF SHOWERS LOOKS TO BE A NARROW ONE, AND EXPECT MUCH OF THE  
AREA TO DRY OUT DURING THE AFTERNOON. ARRIVAL OF MAIN MID LEVEL WAVE  
AND PASSAGE OF COLD FRONT TO CONTINUE AT LEAST SOME SHOWER THREAT  
WEDNESDAY NIGHT INTO THURSDAY (ESPECIALLY DURING THE MORNING). WOULD  
LIKE TO STRESS FORECAST WILL UNFORTUNATELY LOOK MUCH WETTER THAN IT  
WILL ACTUALLY BE, WITH MUCH OF WEDNESDAY NIGHT INTO THURSDAY  
REMAINING DRY (VERY POSSIBLE SOME AREAS SEE LITTLE PRECIPITATION AT  
ALL). CLOUDS AND SHOWERS WILL KEEP TEMPERATURES DOWN A BIT ON  
WEDNESDAY. THURSDAY'S HIGHS WILL BE HIGHLY PREDICATED ON TIMING OF  
COLD FRONTAL PASSAGE. TRENDS CONTINUE TO SUPPORT HIGHS IN THE 70S  
ACROSS A GOOD PORTION OF NORTHERN LOWER MICHIGAN. WE SHALL SEE.  
 
BREAK IN THE ACTIVE WEATHER EXPECTED LATER THURSDAY INTO THURSDAY  
NIGHT, WITH THAT ARRIVAL OF THAT NEXT WAVE RETURNING THE RAIN  
CONCERNS HEADING INTO FRIDAY (TIMING SUBJECT TO CHANGE OF COURSE).  
SIGNALS POINT TO A RESPECTABLE MOISTURE SURGE WITH BOTH A PACIFIC  
AND WESTERN GULF OF MEXICO MOISTURE PLUME ADVECTING NORTH. STILL  
SIGNIFICANT QUESTION ON WHERE BEST DEEP LAYER DYNAMICS WILL PASS.  
STILL SOME HINTS OF THUNDER POTENTIAL AS INSTABILITY AND MID LEVEL  
JET DYNAMICS INCREASE. PLENTY OF TIME TO MONITOR THIS POTENTIAL IN  
THE NEXT FEW DAYS.  
   
LONG TERM
 
(FRIDAY NIGHT THROUGH TUESDAY)  
ISSUED AT 320 PM EDT TUE MAY 21 2019  
 
HIGH IMPACT WEATHER POTENTIAL: MINIMAL  
 
SHOWER AND POTENTIAL THUNDERSTORM THREAT CONTINUES FRIDAY NIGHT,  
WITH RELATIVELY QUIET CONDITIONS EXPECTED THEREAFTER THROUGH THE  
HOLIDAY WEEKEND. CAN'T COMPLETELY RULE OUT A FEW LIGHT SHOWERS AT  
TIMES THROUGH MEMORIAL DAY, ALTHOUGH TRENDS DEFINITELY SUPPORT  
ANYTHING BUT A WASHOUT. TEMPERATURES ALSO LOOK FAIRLY SEASONAL,  
PERHAPS TRENDING A BIT COOLER ON MONDAY. GUIDANCE CONSENSUS BLEND  
APPROACH RETURNS MORE BONAFIDE RAIN CONCERNS ON TUESDAY AS THE NEXT  
WESTERN WAVE ARRIVES. PLENTY OF TIME FOR THAT TO CHANGE.  
 

 
   
AVIATION
 
(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)  
ISSUED AT 705 PM EDT TUE MAY 21 2019  
 
A WARM FRONT WILL LIFT INTO MICHIGAN OVER THE NEXT 24 HOURS...  
PRODUCING A GOOD CHANCE OF SHOWERS ACROSS ALL OF NORTHERN LOWER  
MICHIGAN LATER TONIGHT INTO WEDNESDAY. OVERALL CONDITIONS WILL  
REMAIN VFR DESPITE INCREASING CHANCES OF SHOWERS. LLWS WILL  
DEVELOP LATE TONIGHT...MAINLY ACROSS NW LOWER MICHIGAN  
(PLN/TVC/MBL). SURFACE WINDS WILL REMAIN FROM THE SE AOB 10 KTS  
TONIGHT AND WILL THEN STRENGTHEN TO 15 TO 25 KTS WITH HIGHER GUST  
ON WEDNESDAY.  
 

 
   
MARINE
 
 
ISSUED AT 320 PM EDT TUE MAY 21 2019  
 
HIGH PRESSURE WILL MOVE OFF TO THE EAST. AS A RESULT SOUTHEAST WINDS  
WILL INCREASE LATER TONIGHT INTO TUESDAY AFTERNOON. SMALL CRAFT  
ADVISORIES WILL BE NEEDED ACROSS MUCH OF THE MARINE NEARSHORE AREAS  
DURING THAT TIME. AFTER LIGHTER WINDS WEDNESDAY NIGHT, WINDS WILL  
PICK UP ONCE AGAIN THURSDAY WITH SMALL CRAFT ADVISORY GUSTS  
POSSIBLE. MEANWHILE, THERE WILL BE A FEW SHOWERS THAT MOVE  
THROUGH THE AREA LATER TONIGHT INTO WEDNESDAY.  
 

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

 
 

 
 
UPDATE...MR  
NEAR TERM...MB  
SHORT TERM...AS  
LONG TERM...AS  
AVIATION...MR  
MARINE...MB  
 
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