892  
FXUS63 KTOP 221120  
AFDTOP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TOPEKA KS  
620 AM CDT SUN OCT 22 2017  
   
..UPDATE TO AVIATION FORECAST DISCUSSION
 
 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 326 AM CDT SUN OCT 22 2017  
 
AN UPPER LEVEL TROUGH WAS PROGRESSING EASTWARD INTO THE PLAINS THIS  
MORNING AT 0730Z WITH THE TROUGH AXIS ACROSS WESTERN KANSAS.  
PRECIPITATION WAS ON THE WANE AND SHOULD EXIT THE EASTERN COUNTIES  
BY 09Z THIS MORNING. THE UPPER TROUGH WILL MOVE OVER EASTERN KANSAS  
THIS MORNING WITH THE AXIS MOVING INTO MISSOURI THIS AFTERNOON.  
OVERALL WILL SEE A DECREASE IN CLOUDS THROUGH MID MORNING IN THE  
EAST WITH SUNNY SKIES EXPECTED BY AFTERNOON. TEMPERATURES TODAY WILL  
TOP OUT IN THE UPPER 60S TO AROUND 70 WITH LOWER HUMIDITY AS DRY AIR  
ADVECTION CONTINUES THROUGH THE DAY. TONIGHT WINDS SHIFT BACK TO THE  
SOUTHWEST ON THE ON THE BACKSIDE OF THE SURFACE HIGH AND TROUGHING  
IN THE WESTERN PLAINS WHICH WILL KEEP WINDS IN THE 5 TO 10 MPH RANGE  
THROUGH THE NIGHT. A COLD FRONT WILL MOVE SOUTHEAST ACROSS THE  
CENTRAL PLAINS OVERNIGHT AS AN MID LEVEL TROUGH MOVES ACROSS THE  
NORTHERN PLAINS. HOWEVER THE FRONT IS FORECAST TO EXTEND FROM  
NORTHWEST IOWA TO ACROSS PARTS OF NORTH CENTRAL AND NORTHEAST KANSAS  
LATE TONIGHT.  
   
LONG TERM
 
(MONDAY THROUGH SATURDAY)  
ISSUED AT 326 AM CDT SUN OCT 22 2017  
 
THE WEEK AHEAD WILL FEEL LIKE FALL AND BRING MUCH COOLER AIR INTO  
THE REGION BY THURSDAY AND FRIDAY NIGHT WITH POSSIBLY SOME RAIN/SNOW  
MIX OVER PORTIONS OF THE AREA.  
 
NORTHWEST FLOW SETS UP INTO MONDAY WITH A HIGHLY AMPLIFIED RIDGE IN  
THE WEST. THIS WILL ALLOW FOR A COUPLE ALBERTA LOW SYSTEMS TO  
EMERGE OUT OF SOUTHWESTERN PORTIONS OF CANADA AND BRING A FEW SHOTS  
OF COLDER CONTINENTAL POLAR AIRMASSES INTO THE NORTH CENTRAL CONUS  
AND DOWN INTO PORTIONS OF THE CENTRAL PLAINS. THE FIRST UPPER  
TROUGH DIVES INTO THE NORTHERN PLAINS AND UPPER MS VALLEY AND  
UNDERGOES DEEPENING AND CYCLOGENESIS ON MONDAY PUSHING THE FIRST  
COLD FRONT INTO THE AREA BY THE MORNING HOURS. A TIGHT PRESSURE  
GRADIENT SHOULD SET UP OVER THE REGION AND BRING WINDY CONDITIONS  
WITH CAA ON BOTH MONDAY AND TUESDAY. COULD FLIRT WITH ADVISORY  
LEVEL WINDS DURING THESE TIMES. PROBABLY SOME CONCERN FOR VERY HIGH  
FIRE DANGER TOO OVER PORTIONS OF NORTH CENTRAL KS WITH WINDS AND  
LOW RH IN PLACE. COLDER AIR SETTLES INTO THE AREA BY TUESDAY NIGHT  
WITH LOWS INTO THE 30S AND COULD BE SOME AREAS OF FROST. WILL HOLD  
OFF ON ANY HEADLINES UNTIL LATER SHIFTS SHOULD THEY BECOME NEEDED.  
 
TEMPS REBOUND BRIEFLY ON WEDNESDAY AS THE FIRST TROUGH LIFTS INTO  
THE EASTERN GREAT LAKES AND SHORTWAVE RIDGING TAKES ITS PLACE. THE  
SECOND AND MORE SIGNIFICANT TROUGH DIGS INTO THE AREA THURSDAY AND  
DEEPENS CAUSING SURFACE CYCLOGENESIS MAINLY OVER THE MS VALLEY INTO  
THE GREAT LAKES REGION AGAIN. CAA INCREASES INTO THE THURSDAY NIGHT  
AND INTO FRIDAY AGAIN WITH TEMPS DROPPING INTO THE LOW 30S AND  
POSSIBLY SOME 20S ON FRIDAY WHICH MAY RAISE THE NEED FOR A FREEZE  
WARNING IN THE LATE GROWING SEASON. PRECIP CHANCES REMAIN SMALL ON  
FRIDAY. THIS IS A MAIN MODEL DISCREPANCY AT THE CURRENT TIME. GFS  
IS MAINLY DRY WITH A DRY SLOT THROUGH THE REGION AND THE ECMWF  
DEVELOPS A FRONTOGENETICAL RESPONSE OVER PORTIONS OF THE AREA. IF  
PRECIP DOES FALL, COULD BE A RAIN/SNOW MIX EARLY FRIDAY BEFORE  
TRANSITION GOES TO ALL RAIN. TOO EARLY TO TELL ALL THE DETAILS, BUT  
RIGHT NOW THERE WILL BE COLD AIR TO WORK WITH AT LEAST.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)  
ISSUED AT 620 AM CDT SUN OCT 22 2017  
 
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. LIGHT WEST TO  
SOUTHWEST WINDS UNDER 10 KTS ARE EXPECTED.  
 

 
   
TOP WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  

 
 

 
 
SHORT TERM...53  
LONG TERM...DRAKE  
AVIATION...53  
 
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