FXUS63 KOAX 072025
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
325 PM CDT SAT MAY 7 2011
.SHORT TERM...TONIGHT
19Z SURFACE ANALYSIS INDICATED HIGH PRESSURE FROM EASTERN SOUTH
DAKOTA INTO CENTRAL NEBRASKA. THIS WILL CONTINUE TO SHIFT EASTWARD
THIS EVENING WITH THE WINDS DIMINISHING LATER THIS AFTERNOON. MAY
SEE A QUICK FALL IN TEMPERATURES EARLY THIS EVENING WITH MAINLY
CLEAR SKIES...LIGHT WINDS AND A VERY DRY LOW LEVEL AIRMASS IN
PLACE. GOING LOWS WERE ON THE COOL SIDE OF THE GUIDANCE ENVELOPE
AND SEE NO REASON TO MAKE MEANINGFUL CHANGES ATTM. LOW-LEVEL WARM
AIR ADVECTION WILL GET GOING THIS EVENING OVER CENTRAL AND WESTERN
NEBRASKA AS H85 RIDGE AXIS SHIFTS EAST OF THE FA. MORNING UPPER
AIR ANALYSIS INDICATED SOME +8 C DEW POINTS OVER THE OZARKS AND
INTO THE SOUTHERN PLAINS. THIS MOISTURE IS LIKELY TO SHIFT
NORTHWARD OVERNIGHT. MASS CONVERGENCE AT THE NOSE OF THE
INCREASING LOW- LEVEL JET ALONG WITH PERSISTENT LOW LEVEL ASCENT
ON THE 305-310 K SURFACES WILL LIKELY LEAD TO CONVECTIVE
INITIATION OVER NORTH CENTRAL NEBRASKA INTO SOUTHERN SOUTH DAKOTA
LATE THIS EVENING. SOME OF THESE SHOWERS AND STORMS WILL MOVE EAST
NORTHEAST AND AFFECT NORTHEAST NEBRASKA AFTER MIDNIGHT. HAVE
INCREASED THE GOING POPS FOR THIS. CLOUD BEARING SHEAR IS LESS
THAN 25 KT...AND WEAK CAPE IN THE HAIL GROWTH ZONE WILL LIKELY
KEEP ANY STORMS IN OUR FA SUB SEVERE TONIGHT.
.LONG TERM...SUNDAY THROUGH SATURDAY.
HEIGHTS BUILD OVER THE PLAINS SUNDAY AND MONDAY...HOWEVER
SHORTWAVE TROUGH ENERGY IN THE SOUTHWEST FLOW ALOFT AND A
STRENGTHENING LOW LEVEL JET RETURNING MOISTURE RICH AIR WILL
AFFECT THE FORECAST AREA. TIMING AND PLACEMENT OF CONVECTION WILL
BE THE PRIMARY FORECAST CONCERNS.
INITIALLY THE BEST CONVERGENCE AND UPWARD VERTICAL MOTION ARE OVER
NORTHEAST NEBRASKA INTO SOUTH DAKOTA AND NORTHERN IOWA. WILL
MAINTAIN ISOLATED TO SCATTERED THUNDERSTORMS IN THE FAR NORTH
SUNDAY MORNING. A 40KT LOW LEVEL JET SUNDAY AFTERNOON WILL
TRANSPORT 16 DEG C H85 DEWPOINTS NORTHWARD INTO THE CWA AND COULD
SEE SOME ISOLATED THUNDERSTORMS WITH THIS...MEANWHILE MID LEVEL
TEMPERATURES WILL BE ON THE RISE WITH +10 TO +12C AT H7. HIGHS
SHOULD TOP OUT IN THE 70S TO LOWER 80S WITH MID CLOUDS IN THE
MORNING AND LOW LEVEL MOISTURE INCREASING IN THE AFTERNOON.
SUNDAY NIGHT ANOTHER SHORTWAVE TROUGH MOVES ACROSS THE FORECAST AREA
WITH MODERATE TO HIGHER ELEVATED INSTABILITY OF 2-4.5K J/KG. THE NAM
(NORTH AMERICAN MESOSCALE) AND THE ECMWF (EUROPEAN CENTRE FOR MEDIUM
RANGE FORECAST) MODELS WEAKEN THE CAP WITH SOME COOLING
ALOFT...WHILE THE GFS (GLOBAL FORECAST SYSTEM) IS ON THE HIGHER END
OF THE INSTABILITY WITH A STRONGER CAP IN PLACE. THINK THE FORCING
WILL BE STRONG ENOUGH NORTH OF THE WARM FRONT TO MAINTAIN
ISOLATED TO SCATTERED THUNDERSTORMS IN THE FORECAST FOR SUNDAY
NIGHT...ESPECIALLY FOR NORTHEAST NEBRASKA...WHICH WILL BE ON THE
EDGE OF THE WARMER MID LEVEL TEMPERATURES. DUE TO THE
INSTABILITY...STEEP LAPSE RATES AND DEEP LAYER SHEAR...SOME OF THESE
STORMS MAY BE STRONG TO SEVERE. THE WARM AIR BUILDS IN FOR MONDAY
WITH THE WARM FRONT LIFTING NORTH AND SHOULD SQUELCH
THUNDERSTORMS. MEANWHILE...SURFACE LOW PRESSURE OVER WESTERN
NEBRASKA AT 12Z MONDAY REORGANIZES OVER EASTERN COLORADO MONDAY
AND TRACKS INTO CENTRAL NEBRASKA BY 06Z MONDAY NIGHT AND TO
NORTHEAST NEBRASKA BY 12Z TUESDAY. THE BULK OF THE MOISTURE AND
LIFT IS NORTH OF THE FORECAST AREA...THUS A DRY FORECAST FOR
MONDAY AND TUESDAY LOOKS ON TRACK. WITH THE HIGHER
DEWPOINTS...THERE IS SOME QUESTION AS TO HOW WARM WE WILL GET. 80S
ARE A GOOD BET AND IF SOME DRIER AIR WORKS INTO THE SOUTHERN
COUNTIES...SHOULD SEE SOME AROUND 90 OR LOWER 90 DEGREE TEMPS.
TUESDAY NIGHT THROUGH SATURDAY. TUESDAY NIGHT THE FRONT IS MOVING
THROUGH AND SOMETHING ISOLATED COULD DEVELOP...HOWEVER THE DRY SLOT
IS IN PLACE AND MOISTURE APPEARS LIMITED. IF BETTER MOISTURE IS IN
PLACE THERE WOULD BE INCREASED PRECIPITATION COVERAGE. THE GFS AND
THE ECMWF DIFFER ON THE FRONTAL LOCATION. THE ECWMF IS SLOWER AND
HAS PRECIPITATION FOCUSED OVER THE LOCAL AREA...WHILE THE GFS IS
FASTER AND HAS TO FOCUS MORE TO THE SOUTHEAST TOWARD ST. JOSEPH AND
KANSAS CITY.
THE LONG RANGE MODELS ARE VERY DIFFERENT AS THE GFS DEVELOPS THE
NORTHERN STREAM TROUGH INTO A CLOSED LOW AND HOLDS ON TO IT THROUGH
SATURDAY. THE ECMWF DEVELOPS THE SOUTHERN STREAM TROUGH WHICH HOLDS
ON TO THE PRECIPITATION INTO THE WEEKEND. THE 12Z ECMWF IS
CONSISTENT WITH IT/S 00Z RUN AND HOLDS ON THE THE PRECIPITATION
THROUGH THE WEEK INTO THE WEEKEND. FOR NOW WILL HOLD ON TO A
SLOWER FRONTAL PASSAGE AND MAINTAIN CHANCE POPS (PROBABILITY OF
PRECIPITATION) WEDNESDAY AND WEDNESDAY NIGHT AND WILL LINGER
PRECPITATION INTO THURSDAY IN THE EAST...BUT WILL KEEP IT DRY
FRIDAY AND SATURDAY.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. WINDS WILL DIMINISH
THIS AFTERNOON AND BECOME SOUTHEAST AFTER 06Z AT ALL TAF LOCATIONS.
SOME INCREASE IN HIGH LEVEL CLOUDS ARE EXPECTED TOWARD 12Z AT
OMA/LNK WITH WINDS INCREASING AFTER 15Z ON SUN. THERE MAY BE AN ISO
SHRA/TSRA POTENTIAL AT OFK FM 09-13Z...BUT MUCH OF THE ACTIVITY IS
EXPECTED TO REMAIN N OF THE TERMINAL...AND WILL KEEP ALL MENTION OUT
OF THE TAF ATTM. WE WILL INCLUDE AN INCREASE IN MID LEVEL CLOUDS AOA
8 K FT AFTER 09Z THOUGH.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
BOUSTEAD/ZAPOTOCNY/BOUSTEAD