518  
FXUS63 KOAX 232050  
AFDOAX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE  
350 PM CDT SUN JUL 23 2017  
   
SHORT TERM
 
(TONIGHT THROUGH MONDAY NIGHT)  
ISSUED AT 321 PM CDT SUN JUL 23 2017  
 
AS ADVERTISED, A SOMEWHAT COOLER AND DRIER AIRMASS CONTINUES TO  
BUILD SOUTH ACROSS THE REGION TODAY WITH TEMPERATURES RANGING FROM  
THE MIDDLE 80S IN NORTHEAST NEBRASKA TO THE LOWER 90S IN FAR  
SOUTHERN REACHES OF THE FORECAST AREA. DEWPOINTS HAVE ALSO DROPPED  
CONSIDERABLY, WITH COMFORTABLE 55-63 DEGREE DEWPOINTS EXPECTED TO  
BE COMMON ACROSS THE ENTIRE AREA BY MID EVENING. SURFACE HIGH  
PRESSURE WILL BUILD SOUTHEAST OVERNIGHT WITH THE SURFACE RIDGE  
AXIS EXTENDING DOWN THE MISSOURI VALLEY BY SUNRISE ON MONDAY. THIS  
SHOULD PROMOTE LIGHT OR CALM WINDS AND EFFECTIVE RADIATIONAL  
COOLING IN THE PRESENCE OF REMNANT NEAR-SURFACE MOISTURE. THESE  
INGREDIENTS SUGGEST AT LEAST THE POTENTIAL FOR PATCHY FOG  
ESPECIALLY IN LOW AREAS ALONG THE MISSOURI VALLEY AND EASTWARD  
INTO WESTERN IOWA. AT THIS TIME, CONFIDENCE IN FOG DEVELOPMENT IS  
LOW BUT IF/WHERE IT DOES DEVELOP, SOME PATCHY DENSE FOG IS  
POSSIBLE.  
 
ON MONDAY, SURFACE WINDS TURN BACK OUT OF THE SOUTHEAST WITH SOME  
WARM ADVECTION GRADUALLY NOSING INTO THE AREA. ALL-IN-ALL IT WILL  
BE A PLEASANT DAY ESPECIALLY WHEN COMPARED TO THE PAST WEEK, WITH  
NEAR-NORMAL TEMPERATURES EXPECTED. THERE IS A VORTICITY MAXIMUM  
CURRENTLY VERY EVIDENT IN WV IMAGERY OVER SW MONTANA WHICH WILL  
SLOWLY BUT SURELY TRACK ACROSS SOUTHERN SOUTH DAKOTA. THIS MAY  
PROVIDE ADEQUATE LIFT TO INITIATE CONVECTION LATE MONDAY INTO  
MONDAY NIGHT MAINLY NEAR THE NE/SD BORDER. LOW LEVELS WILL BE VERY  
DRY BUT MODEL SOUNDINGS (AND WV IMAGERY) SUGGEST MID-LEVEL  
MOISTURE ASSOCIATED WITH THE SYSTEM MAY SUPPORT UNCAPPED  
CONVECTIVE PARCELS OVER FAR NORTHERN NE AND PERHAPS INTO WEST  
CENTRAL IA. SEVERE POTENTIAL IS LOW AS THE ELEVATED INSTABILITY  
AND EFFECTIVE SHEAR ARE NOT PARTICULARLY IMPRESSIVE.  
 
WARMER WEATHER IS EXPECTED TUESDAY INTO WEDNESDAY AS SOUTH WINDS  
INCREASE AND A STRONG SHORT WAVE TROUGH TRACKS ACROSS SOUTHERN  
CANADA. THIS TROUGH WILL PUSH A COLD FRONT TOWARD NORTHERN PARTS  
OF THE FORECAST AREA BY EARLY WEDNESDAY MORNING WHILE REINFORCING  
SHORT WAVE ENERGY GRADUALLY PUSHES THE FRONT THROUGH THE WHOLE CWA  
BY THURSDAY. SHOULD SEE QUITE A BIT OF CONVERGENCE ALONG THIS SLOW  
MOVING FRONTAL BOUNDARY WHILE THE INTERACTION WITH THE MODIFIED  
MONSOONAL MOISTURE PLUME AND WEAK PERIODS OF MID/UPPER LEVEL  
ENERGY TO PRODUCE A FEW ROUNDS OF THUNDERSTORMS. HAVE THUS GONE  
WITH RELATIVELY HIGH PRECIP CHANCES FOR THE GENERAL WEDNESDAY TIME  
FRAME WITH THE EXCEPTION THAT THE ACTIVITY WILL BE SCATTERED IN  
NATURE AND A FEW LOCATIONS MAY STILL VERY WELL GO UNTOUCHED BY  
PRECIPITATION. IN THE END THOUGH, THE SLOW MOVEMENT OF THE SYSTEM  
AND AVAILABILITY OF MULTIPLE FORCING MECHANISMS SUGGEST THAT  
HIGHER END POPS ARE REASONABLE.  
 
TEMPERATURES BEHIND THIS SYSTEM MAY ACTUALLY FALL BELOW NORMAL FOR  
MULTIPLE DAYS AS A NORTHWEST TO NEARLY MERIDIONAL FLOW PATTERN IS  
SET TO DOMINATE THE LOCAL FORECAST AREA.  
   
LONG TERM
 
(TUESDAY THROUGH SUNDAY)  
ISSUED AT 321 PM CDT SUN JUL 23 2017  
 
WARMER WEATHER IS EXPECTED TUESDAY INTO WEDNESDAY AS SOUTH WINDS  
INCREASE AND A STRONG SHORT WAVE TROUGH TRACKS ACROSS SOUTHERN  
CANADA. THIS TROUGH WILL PUSH A COLD FRONT TOWARD NORTHERN PARTS  
OF THE FORECAST AREA BY EARLY WEDNESDAY MORNING WHILE REINFORCING  
SHORT WAVE ENERGY GRADUALLY PUSHES THE FRONT THROUGH THE WHOLE CWA  
BY THURSDAY. SHOULD SEE QUITE A BIT OF CONVERGENCE ALONG THIS SLOW  
MOVING FRONTAL BOUNDARY WHILE THE INTERACTION WITH THE MODIFIED  
MONSOONAL MOISTURE PLUME AND WEAK PERIODS OF MID/UPPER LEVEL  
ENERGY TO PRODUCE A FEW ROUNDS OF THUNDERSTORMS. HAVE THUS GONE  
WITH RELATIVELY HIGH PRECIP CHANCES FOR THE GENERAL WEDNESDAY TIME  
FRAME WITH THE EXCEPTION THAT THE ACTIVITY WILL BE SCATTERED IN  
NATURE AND A FEW LOCATIONS MAY STILL VERY WELL GO UNTOUCHED BY  
PRECIPITATION. IN THE END THOUGH, THE SLOW MOVEMENT OF THE SYSTEM  
AND AVAILABILITY OF MULTIPLE FORCING MECHANISMS SUGGEST THAT  
HIGHER END POPS ARE REASONABLE.  
 
TEMPERATURES BEHIND THIS SYSTEM MAY ACTUALLY FALL BELOW NORMAL FOR  
MULTIPLE DAYS AS A NORTHWEST TO NEARLY MERIDIONAL FLOW PATTERN IS  
SET TO DOMINATE THE LOCAL FORECAST AREA.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)  
ISSUED AT 1215 PM CDT SUN JUL 23 2017  
 
A SURFACE RIDGE AXIS ANALYZED FROM THE DAKOTAS INTO WESTERN NE AS  
OF 17Z WILL BUILD SOUTHEAST THROUGH THE REGION WITH THE POTENTIAL  
FOR SOME FOG FORMATION AT KOMA NEAR OR SHORTLY AFTER DAYBREAK ON  
MONDAY. OTHERWISE, VFR CONDITIONS WILL PREVAIL THROUGH FORECAST  
PERIOD.  
 

 
   
OAX WATCHES/WARNINGS/ADVISORIES
 
 
NE...NONE.  
IA...NONE.  

 
 

 
 
SHORT TERM...BARJENBRUCH  
LONG TERM...BARJENBRUCH  
AVIATION...MEAD  
 
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