886  
FXUS63 KAPX 231028  
AFDAPX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GAYLORD MI  
628 AM EDT WED APR 23 2014  
   
SYNOPSIS
 
 
ISSUED AT 335 AM EDT WED APR 23 2014  
 
HIGH PRESSURE BUILDING INTO THE UPPER GREAT LAKES TODAY WILL BRING  
MUCH DRIER CONDITIONS TO THE STATE. THE NEXT CHANCE FOR  
PRECIPITATION COMES LATE THURSDAY AND THURSDAY NIGHT AS LOW PRESSURE  
MOVES INTO THE GREAT LAKES. THERE IS A CHANCE OF SOME WET SNOW WITH  
THIS SYSTEM ACROSS THE UPPER PENINSULA. COOL TEMPERATURES WILL  
CONTINUE THROUGH THE UPCOMING WEEKEND.  
 

 
   
SHORT TERM
 
(TODAY THROUGH TONIGHT)  
ISSUED AT 335 AM EDT WED APR 23 2014  
   
..COOL BUT VERY NICE OUT
 
 
 
IMPACTS: NONE.  
 
CURRENT WEATHER AND SYNOPTIC PATTERN/EVOLUTION:  
 
UPPER LEVEL TIGHTER NW FLOW/JET MOVING IN OVERHEAD WITH DOWNWARD  
VERTICAL MOTIONS...AND INVADING HIGH PRESSURE. THE TIGHT PRESSURE  
GRADIENT/H8 JET IS NOW EXITING OUT OF THE REGION...AND WINDS WERE  
DYING DOWN. THE BACK EDGE OF THE LOW LEVEL COLD POOL AND TRAPPED  
MOISTURE FROM THE DOWNWARD MOTIONS/WEAK INVERSION IS/HAS EXITED MUCH  
OF THE CWA. SKIES ARE RATHER CLEAR...WITH DEW POINTS LINGERING  
HIGH...BUT ANY FOG HAS NOT BEEN ABLE TO DEVELOP DUE TO STILL A  
GOOD NIGHT TIME WIND OUT THERE.  
 
DEEP DRY AIR SETTLES IN TODAY WITH THE HIGH PRESSURE...BUT MIXING  
WILL BE RELATIVELY SHALLOW. THE SOURCE REGION FOR THIS AIR IS  
ONTARIO WHERE TD'S YESTERDAY AFTERNOON DROPPED AS LOW AS 9F PER  
OBS. MOST AREAS WERE IN THE TEENS TO AROUND 20F...BUT DATA IS  
SPARSE IN THE MAIN SOURCE REGION...PLUS...NUMBERS ARE LIKELY A  
SHADE HIGH DUE TO SNOW COVER AND SOME RECENT MELTING. FURTHER  
ANALYSIS OF FCST BFR SOUNDINGS SUGGEST MIXING OUT TO ROUGHLY 12F-  
17F....FOR MOST OF THE REGION. TEMPERATURES WILL CLIMB TO THE  
MIDDLE 40S IN EASTERN UPPER...AS WELL AS DOWNWIND OF THE COLDER  
LAKES...WITH THE LOWER HALF OF THE 50S AWAY FROM THE LAKES IN NRN  
LOWER. THIS WILL BRING RH'S DOWN INTO CURRENT FORECAST VALUES OF  
UPPER TEENS TO LOWER 20S FOR THOSE AREAS AWAY FROM THE LAKES IN  
NRN LOWER. QUITE DRY. WINDS WILL BE LIGHT WITH SFC HIGH PRESSURE  
OVERHEAD AND TEMPERATURES WELL BELOW THRESHOLDS FOR ANY ELEVATED  
FIRE WEATHER CONCERNS. HIGH PRESSURE REMAINS OVERHEAD THROUGH THE  
NIGHT.  
 
 
GENERAL WEATHER EXPECTATIONS:  
 
CLEAR SKIES WILL REMAIN CLEAR FOR THE WHOLE DAY WITH LITTLE TO NO  
CLOUDS EXPECTED THROUGH MUCH OF THE DAY. SOME HIGH LEVEL CIRRUS WILL  
ROAM THE GTV BAY REGION LATER THIS AFTERNOON...AND WILL GRADUALLY  
EXPAND ACROSS THE REGION TONIGHT. WINDS WILL BE OUT OF THE NW EARLY  
WITH SOME GUSTINESS ACROSS NE LOWER...BEFORE DYING OFF AND BECOMING  
WEAK LATER TODAY AND ESPECIALLY TONIGHT WITH HIGH PRESSURE PARKED  
OVERHEAD. LOWS WILL BE ABLE TO DIP INTO THE MIDDLE 20S TO AROUND  
30F. IT'LL FEEL DRIER OUT THERE FOR SURE.  
   
LONG TERM
 
(THURSDAY THROUGH TUESDAY)  
ISSUED AT 335 AM EDT WED APR 23 2014  
 
OVERVIEW...A 500 MB TROUGH MOVING THROUGH THE PAC NW IS SETTING THE  
STAGE FOR THE REST OF THE WEEK. THE RIDGE IN THE PLAINS WILL MOVE  
INTO THE UPPER GREAT LAKES TODAY AND THURSDAY. HOWEVER, BY THURSDAY  
NIGHT AND FRIDAY, THE 500 MB TROUGH THEN MOVES INTO THE UPPER GREAT  
LAKES. BY SATURDAY, AND THEN BEYOND...A SECOND TROUGH DIVES INTO THE  
PLAINS AND BRINGS THE COLD SNAP THAT THE MODELS HAVE BEEN  
ADVERTISING.  
 
(4/24)THURSDAY...IT STILL SEEMS LIKE A QUESTION MARK. THE 12Z GFS  
MUST HAVE BROUGHT THE RAIN IN A LITTLE MORE. HOWEVER, LOOKING AT THE  
12Z ECMWF AND THE 00Z GFS, I'M WONDERING WITH THE MOISTURE PROFILES  
THAT THE RAIN DOESN'T HOLD OFF A BIT LONGER. THE 12Z ECMWF MODELS  
SOUNDINGS SHOW A DEEPER DRY LAYER UNDER THE RETURN FLOW OF THE  
HUDSON BAY HIGH. IN FACT, WITH THE 850 MB MOISTURE SHOWING ON THE  
ECMWF THAT EVEN IT'S QPF FIELD IS A LITTLE AGGRESSIVE. SO TRIED A  
BLENDED APPROACH BY TAKING THE ECMWF 12Z AND THE GOING FORECAST.  
THIS CUT SOME OF THE POPS, BUT LEAVES THE CHANCE POPS IN THE SW  
COUNTIES, NEAR TVC AND MBL.  
 
THURSDAY NIGHT...THIS TIME FRAME WAS NEVER IN QUESTION AS THE LOWER  
LEVEL MOISTURE BEGINS TO GET BETTER COORDINATED WITH THE UPPER LEVEL  
MOISTURE ALONG THE SFC TROUGH. IT'S JUST THAT THE GFS BEGINS TO OUT  
RACE THE ECWMF AND PULLS BOTH THE 500 MB AND SFC LOW IN C UPPER BY  
12Z. THE ECMWF HAS A SHALLOWER SFC DEPRESSION, WITH THE 500 MB LOW  
IN ONTARIO AND NORTHERN LAKE SUPERIOR. FROM THE WPC DISCUSSION ON  
THE MODELS THEY ARE TRENDING TOWARD THE MORE NORTHERN SOLUTION THAT  
IS A COMPROMISE BETWEEN THE NAM AND UKMET. WHICH SEEMS CLOSER TO THE  
ECMWF IDEA.  
 
(4/25)FRIDAY...IF WE STAY CLOSER TO THE ECMWF IDEA THEN WILL KEEP  
THE GOING TEMPERATURES AS THE MODELS THAT ARE GFS INFLUENCED ARE  
QUITE COLD. HOWEVER, IN THE OFF CHANCE THAT THE GFS IS RIGHT, THEN  
THE TEMPERATURES WILL BE OFF BE QUITE A LOT. OTHERWISE, THE OCCLUDED  
FRONT WILL PUSH THROUGH THE REGION BRINGING AN END TO THE RAIN BY  
00Z. OVERNIGHT, THE GFS GETS REALLY COLD WITH THE 850 MB  
TEMPERATURES FALLING TO AROUND -6C WHILE THE ECMWF REMAINS AROUND 0C  
NEAR THE STRAITS. SO WILL HAVE RAIN OR SNOW AS THE LAST OF THE  
PRECIPITATION COMES TO AN END. THE ECWMF DRIES OUT THE UPPER LEVELS  
(700-500 MB), WHILE THE GFS IS VERY WET. AGAIN, IF THE WPC  
DISCUSSION IS RIGHT WITH THE IDEA THAT MOST OF THE MODELS ARE  
BACKING OFF OF THE SOUTHERN TRACK, THEN THE GFS IS TOO COLD.  
 
EXTENDED (SATURDAY THROUGH TUESDAY)...(4/26)SATURDAY...WILL CONTINUE  
THE DRY IDEA WITH THE DRY AIR PUSHING INTO THE REGION.  
(4/27)SUNDAY...THE MODELS STILL HAVE A STRONG HUDSON BAY HIGH IN THE  
UPPER GREAT LAKES. HOWEVER, THE ECMWF BEGINS TO DROP A 500 MB LOW  
INTO THE EASTERN US, INCLUDING THE UPPER GREAT LAKES, WHICH HELPS TO  
BRING MOISTURE UP ALONG THE WARM FRONT THAT IS FORMING UP IN  
MICHIGAN. THE GFS HAS A HIGHLY AMPLIFIED RIDGE THAT KEEPS THE RAIN  
OUT OF MICHIGAN. PUT LOW CHANCE POPS IN THE SW COUNTIES OVERNIGHT AS  
THE SYSTEM DEVELOPS. (4/28)MONDAY...RAIN BEGINS TO MOVE INTO THE  
REGION ON THE GFS, AND IS ALREADY HERE FOR THE ECMWF, SO WILL  
CONTINUE THE CHANCE FOR RAIN. THE ECWMF IS MUCH COLDER, SO WILL HAVE  
SNOW OR RAIN OVERNIGHT. (4/29)TUESDAY...THE GFS IS DRY, THE ECMWF  
WET. IT WILL DEPEND ON WHERE THE 500 MB LOW CUTS OFF. SO A CHANCE OF  
RAIN OR SNOW DEPENDING ON THE MODEL SOLUTION.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)  
ISSUED AT 625 AM EDT WED APR 23 2014  
 
VFR FOR THE ENTIRE TAF PERIOD  
 
HIGH PRESSURE WILL SETTLE IN OVER THE REGION TODAY AND TONIGHT  
RESULTING IN LIGHT WINDS (MAYBE JUST A BIT GUSTY OUT OF THE NW AT  
APN). VERY DRY AIR IN PLACE WILL ALSO LIMIT ANY CLOUDS TO JUST  
SOME INCREASING HIGH CLOUDS FROM LATE THIS AFTERNOON THROUGH  
TONIGHT.  
 

 
   
MARINE
 
 
ISSUED AT 335 AM EDT WED APR 23 2014  
 
HIGH PRESSURE SETTLES IN TODAY AND TONIGHT WITH NW WINDS BECOMING  
LIGHT AND VARIABLE...AND WAVES IN ICE FREE AREAS MINIMAL. WAVES  
GET A LITTLE ROUGHER THURSDAY WITH DEVELOPING EASTERLY WINDS AHEAD  
OF INVADING LOW PRESSURE AND RAIN...ALTHOUGH THE STABILITY WILL BE  
ON THE RISE. WINDS BECOME LIGHTER AND MORE VARIABLE FRIDAY AS LOW  
PRESSURE MOVES IN OVER NRN MICHIGAN.  
 

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

 
 

 
 
SYNOPSIS...JL  
SHORT TERM...SMD  
LONG TERM...JL  
AVIATION...SMD  
MARINE...SMD  
 
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