Forecast Discussion
NWS Omaha/Valley, NE

000
FXUS63 KOAX 312015
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
315 PM CDT SAT JUL 31 2010

.SHORT TERM...TONIGHT AND SUNDAY.
POTENTIAL FOR FOG TONIGHT IS THE MAIN CONCERN IN THE SHORT TERM...
BUT WILL NOT ISSUE AN ADVISORY AT THIS TIME. SURFACE ANALYSIS EARLY
THIS AFTN SHOWED WEAK HIGH PRESSURE STRETCHING FROM MN INTO WRN IA
AND ERN NE...THEN INTO NRN KS. THIS HIGH WILL BE MOVING EWD TNGT...
WITH LOW PRESSURE MOVING FROM ERN MT INTO WRN SD. S OR SE LOW LEVEL
WINDS WILL BE INCREASING TNGT SO FOG SHOULD NOT GET AS WIDESPREAD
OR AS DENSE COMPARED TO EARLY THIS MORNING. DEWPOINTS ACROSS THE
LOCAL AREA WERE QUITE VARIABLE...RANGING FROM THE LOWER 60S TO THE
MID 70S. LOWS TONIGHT SHOULD RANGE MAINLY FROM 64 TO 68 BUT A FEW
SPOTS MAY BE COOLER THAN THAT DEPENDING ON FOG. BEST FOCUS FOR TSTMS
TNGT WILL BE WELL TO THE NORTH IN THE DKTS AND WRN MN NORTH OF A
WARM FRONT.

SUNDAY...S WINDS WILL CONTINUE AND CHANCE OF PCPN STILL LOOKS SMALL.
MOS GUIDANCE SEEMS REASONABLE SO KEPT HIGHS IN THE UPPER 80S AND
LOWER 90S.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY.
TSTM CHANCES AND TIMING WILL PROVIDE THE PRIMARY FORECAST CHALLENGES
THROUGH THIS PERIOD.

MODEL SHOW 850 MB DEWPOINTS INCREASING TO ABOUT 15 DEGREES C IN OUR
FAR WESTERN COUNTIES BY 00Z MONDAY. WILL KEEP TREND OF THE PREVIOUS
FCST AND SPREAD TSTM CHANCE ACROSS THE AREA SUNDAY NIGHT AS 850 MB
MOISTURE AND ELEVATED INSTABILITY MOVE IN. SEVERE WEATHER DOES NOT
LOOK LIKELY.

MONDAY IS A DIFFERENT STORY THOUGH. A COLD FRONT WILL BE PUSHING
INTO THE AREA. AN MCS APPEARS POSSIBLE FROM NERN NE INTO SWRN IA IN
THE AFTN AND EVENING. ML CAPE VALUES FROM THE NAM REACH OVER 5000
J/KG. IT APPEARS THERE WILL BE DECENT SHEAR...SO THIS WILL HAVE TO
BE WATCHED. STORMS WILL PROBABLY TRY TO DEVELOP NORTHEAST DURING
THE NIGHT ACROSS IA...SIMILAR TO DEPICTION FROM 12Z NAM. FRONTAL
BOUNDARY REMAINS IN THE AREA TUESDAY AND TUESDAY NIGHT...SO KEPT
POPS 20-35 PERCENT.

LARGE SCALE 500 MB PATTERN REALLY DOES NOT CHANGE A LOT THROUGH THE
WEEK. THE CENTER OF A RIDGE SHOULD REMAIN OVER THE LOWER MISSISSIPPI
RIVER VALLEY OR THE SRN PLAINS. A TROUGH SHOULD STRENGTHEN SLIGHTLY
OVER THE WRN U.S. TOWARD NEXT WEEKEND. KEPT SOME SLIGHT CHANCES IN
AT TIMES LATER IN THE WEEK.

&&

.AVIATION...
TAF SITES KOFK/KOMA/KLNK

18Z TAFS

HIGH PRESSURE AREA WILL MOV EASTWARD INTO MO/IA/IL BY 01/18Z.  LIGHT
WINDS TONIGHT MAY AGAIN PRODUCE FOG AT KOMA AND KLNK. DUE TO STRONGER
SOUTHERLY RETURN FLOW...FOG MAY NOT BE MUCH OF A PROBLEM AT KOFK.
BETWEEN 10Z-14Z...VISIBILITIES MAY BE REDUCED AS MUCH AS 1 1/2 SM
AT KOMA. AFTER 01/15Z...WINDS WILL BECOME SOUTH TO SOUTHEAST AND VFR
CONDITIONS SHOULD PREVAIL.

&&

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

$$

DISCUSSION...MILLER
AVIATION...SMITH

NWS OAX Office Area Forecast Discussion

Forecast Discussion
NWS Hastings, NE

000
FXUS63 KGID 312221
AFDGID

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HASTINGS NE
521 PM CDT SAT JUL 31 2010

.AVIATION...00Z TAF. VFR CONDITIONS ARE EXPECTED THROUGH MOST OF THE
TAF PERIOD...AS HIGH PRESSURE MOVES EAST AND MOIST...SOUTHERLY OR
SOUTHEAST FLOW DEVELOPS. THAT MAY RESULT IN A PERIOD OF BRIEFLY
MVFR CONDITIONS AROUND SUNRISE...BUT REDUCED VISIBILITIES SHOULDN/T
BE AS LOW OR WIDESPREAD AS THIS MORNING. MID WARM ADVECTION ALONG
WITH INCREASING MOISTURE WILL PROBABLY TRIGGER A MID LEVEL ACCAS
CLOUD DECK DURING THE MORNING HOURS.

&&

.PREV DISCUSSION... /ISSUED 310 PM CDT SAT JUL 31 2010/

SHORT TERM...TONIGHT THROUGH SUNRISE MONDAY. MAIN CONCERN WILL BE
TEMPERATURES ALONG WITH SMALL CHANCES FOR TSTMS ESPECIALLY SUNDAY
NIGHT.

SATELLITE WATER VAPOR IMAGERY...UPPER AIR ANALYSIS AND WIND PROFILER
NETWORK SHOWING UPPER LOW HAS MOVED INTO THE PACIFIC NW COAST WITH
JET ACROSS THE NORTHERN PLAINS AND THEN DIVING SOUTHEAST INTO THE
OHIO RIVER VALLEY. WEAK RIDGING FROM THE ROCKIES TO THE CENTRAL
PLAINS WITH SEVERAL SUBTLE SHORTWAVES MOVING THROUGH THE FLOW.
SURFACE ANALYSIS HAS HIGH PRESSURE OVER OUR CWA...ODX TO GRI AT 18Z.
SOME LOCATIONS HAVE MIXED OUT WITH DEWPOINTS IN THE LOWER 60S WHILE
OTHER SPOTS STILL AROUND 70. TEMPERATURES RUNNING SIMILAR TO
YESTERDAY AND EXPECT HIGHS TO RANGE FROM THE MID/UPPER 90S SOUTH TO
THE LOW 90S NORTH. WEAK SURFACE BOUNDARY THAT MOVED THROUGH EARLY
FRIDAY IS NOW LOCATED ACROSS NORTHERN OK. TSTMS HAD ALREADY
DEVELOPED OVER EASTERN CO.

AFTER LOOKING AT FORECAST SOUNDINGS...PROGGED 850 TEMPS...MOS
GUIDANCE...ETC THINK SUNDAY WILL BE SLIGHTLY WARMER THAN TODAY. LOWS
TONIGHT SHOULD BE NEAR 70 GIVE OR TAKE A COUPLE OF DEGREES AND THEN
A DEGREE OR TWO WARMER SUNDAY NIGHT.

TSTM CHANCES CONTINUE TO BE A CHALLENGE. CONVECTION BROKE EARLY THIS
MORNING JUST TO THE SOUTH OF OUR CWA. WITH BOUNDARY A LITTLE FURTHER
SOUTH THINK WE SHOULD REMAIN DRY BUT ONE CONCERN IS HOW FAR THE
ACTIVITY IN EASTERN CO WILL PROGRESS OUR WAY. 4KM WRF SHOWS THIS
REMAINING WELL TO OUR WEST WITH BETTER UPSLOPE.  BETTER CHANCES LOOK
TO BE SUNDAY NIGHT AS CONVECTION FIRES TO THE NORTH FROM SDAK INTO
NORTHERN NEB ALONG THE SURFACE TROUGH AND THEN WORKS ESE OVERNIGHT.
WILL BOOST POPS INTO CHANCE CATEGORY IN THE NORTH AND THEN TAPER
BACK ACROSS THE SOUTH.

LONG TERM...12Z MONDAY THROUGH SATURDAY. THUNDERSTORM CHANCES POSE
THE MAIN CHALLENGE THROUGH THE EXTENDED PERIOD. OTHER AREA OF FOCUS
IS HOT/HUMID CONDITIONS MONDAY...LINGERING INTO TUESDAY ACROSS NORTH
CENTRAL KS.

OVERALL...A FAIRLY TYPICAL SUMMER PATTERN LOOKS TO MAINTAIN A GRIP
ON THE AREA THROUGH THE EXTENDED PERIOD...AS MID/UPPER LEVEL
RIDGING CONTINUES TO DOMINATE THE SOUTHERN TWO THIRDS OF THE
CONUS. THE CWA WILL REMAIN TOWARD THE NORTHERN PERIPHERY OF THE
UPPER RIDGING...ENOUGH UNDER ITS GRASP TO KEEP TEMPERATURES NEAR
OR ABOVE AVERAGE...BUT ALSO STILL IN THE PATH OF MID/UPPER
DISTURBANCES AND POCKETS OF MONSOON MOISTURE PIVOTING AROUND THE
RIDGE TO KEEP THUNDERSTORM CHANCES IN PLAY. SOME OF THE MORE
INTERESTING WEATHER LOOKS TO COME EARLY IN THE PERIOD AS A
SHORTWAVE RIDING EAST ALONG THE US/CANADIAN BORDER WILL PUSH A
COLD FRONT SOUTH INTO THE AREA LATE MONDAY AFTERNOON OR MONDAY
EVENING. STILL SOME TIMING DIFFERENCES BETWEEN MODELS AS THE GFS
HOLDS THE FRONT BACK UNTIL EVENING WHILE THE NAM AND ECMWF BRING
IT IN DURING THE AFTERNOON. FORECAST FOLLOWS THE NAM/ECMWF QUICKER
ARRIVAL...INTRODUCING THUNDERSTORM CHANCES DURING THE AFTERNOON
ACCORDINGLY. AHEAD OF THE FRONT...IT WILL BE VERY HOT AND HUMID AS
SOUTH/SOUTHWEST WINDS ADVECT H85 TEMPS AROUND +30C INTO THE AREA.
SURFACE DEWPOINTS IN THE UPPER 60S TO MID 70S WILL COMBINE WITH
THE HOT AIRMASS TO MAKE FOR A MUGGY DAY. EXPECT HIGH TEMPS TO
RANGE FROM AROUND 90F IN THE NORTH BEHIND THE EARLIER FRONTAL
PASSAGE TO AROUND 103F IN THE SOUTHWEST...WITH HEAT INDICES
REACHING 100F OR HIGHER ACROSS THE SOUTHEAST HALF TO TWO THIRDS OF
THE CWA. NEEDLESS TO SAY GIVEN THIS WARM/HUMID AIRMASS...PLENTY OF
INSTABILITY WILL BE AVAILABLE FOR THE FRONT TO ACT ON. IN
FACT...0-1KM MLCAPES ARE PROGGED TO REACH OVER 3000 OR 3500 J/KG.
DEEP LAYER SHEAR IS WEAK AHEAD OF THE FRONT...BUT IS ACTUALLY
PRETTY DECENT AT 30-35 KTS ALONG AND BEHIND IT. THIS COMBINATION
OF SHEAR AND INSTABILITY WILL SUPPORT SOME RISK FOR SEVERE WEATHER
LATE MONDAY AFTERNOON INTO MONDAY EVENING...WHICH THE HWO AND SPC
DAY 3 OUTLOOK ALREADY HAVE WELL IN HAND. COULD ALSO SEE SOME
LOCALLY HEAVY RAINFALL AS PRECIPITABLE WATERS CLIMB TO AROUND 2
INCHES. THE NOCTURNAL LLJ NOSES INTO THE AREA MONDAY
EVENING...WHICH SHOULD ENHANCE THUNDERSTORM CHANCES...BEFORE
VEERING LATER MONDAY NIGHT AND TAKING BETTER CONVECTIVE CHANCES
EASTWARD WITH IT.

THE FRONT LOSES SOME OF ITS PUSH AND HANGS UP ACROSS OR NEAR THE
SOUTHEAST CWA THROUGH MUCH OF THE DAY ON TUESDAY. FORCING IS NOT AS
FOCUSED AS ON MONDAY WHEN THE FRONT WAS PUSHING THROUGH...HOWEVER
PLENTY OF MOISTURE WILL STILL BE AROUND AS LIGHT NORTHEAST FLOW
NORTH OF THE FRONT KEEPS RICH BOUNDARY LAYER MOISTURE POOLED OVER
THE AREA...WHILE SOME MID/UPPER LEVEL MONSOON MOISTURE GETS ROTATED
OVER THE AREA ON NORTHERN PERIPHERY OF MID/UPPER RIDGE. AVAILABLE
MOISTURE/RESULTANT INSTABILITY...PROXIMITY OF BOUNDARY...AND WEAK
SHORTWAVE RIPPLES LIKELY TRANSLATING THROUGH THE FLOW WILL BRING
MORE THUNDERSTORM CHANCES TUESDAY INTO TUESDAY NIGHT...WITH
CONVECTION LIFTING OUT OF THE HIGH PLAINS ALSO COMING INTO PLAY BY
TUESDAY NIGHT. COULD SEE A COUPLE STRONG STORMS TUESDAY
AFTERNOON/EVENING CONSIDERING AVAILABLE INSTABILITY AND ALSO
POSSIBLY SOME LOCALLY HEAVY RAIN AS PRECIPITABLE WATERS REMAIN
AROUND 2 INCHES. WILL SEE SOME RELIEF FROM THE HEAT NORTH OF THE
FRONT /ALTHOUGH IT WILL REMAIN HUMID/...BUT KS ZONES LOOK TO CLIMB
INTO THE UPPER 90S FOR HIGHS AS THEY REMAIN NEAR OR AHEAD OF THE
FRONT THROUGH MUCH OF THE DAY.

CONFIDENCE IN PRECIP CHANCES DWINDLES WITH TIME AS WOULD BE EXPECTED
IN THIS TYPE OF PATTERN WHERE CHANCES HINGE LARGELY ON SMALL SCALE
FEATURES THAT BECOME INHERENTLY LESS PREDICTABLE WITH TIME. THAT
BEING SAID...WILL MAINTAIN SOME THUNDERSTORM CHANCES WEDNESDAY AND
WEDNESDAY NIGHT EVEN THOUGH FRONT IS SOUTH OF THE AREA BY THIS
TIME...DUE TO MOISTURE PLUME STILL EXTENDING EASTWARD ACROSS THE
AREA ON EDGE OF UPPER RIDGE AND HINTS OF MID-LEVEL RIPPLES STILL
IMPACTING THE AREA. WEDNESDAY NIGHT WILL FEATURE A LITTLE BETTER
CHANCE AS HIGH PLAINS CONVECTION MAY PROPAGATE EAST/NORTHEAST
ALONG EDGE OF LLJ/H85 FRONTAL ZONE...WITH ADDITIONAL DEVELOPMENT
FARTHER EAST ALONG THIS ZONE POSSIBLE AS WELL. WILL TRY TO KEEP
THURSDAY DRY FOR THE TIME BEING AS PLUME OF MOISTURE TRIES TO SLIP
EAST BY THIS TIME...ALTHOUGH A LITTLE MORE PRONOUNCED SHORTWAVE
WILL BRING PRECIP CHANCES BACK TO AT LEAST NORTHWEST PORTIONS OF
THE AREA THURSDAY NIGHT. THIS SHOULD SLIDE EAST/NORTHEAST BY
FRIDAY...AND WILL MAINTAIN A DRY FORECAST FOR FRIDAY AND SATURDAY
WITH NOTHING TOO SOLID TO LATCH ONTO AT THIS POINT. TEMPS WILL BE
ON THE RISE ONCE AGAIN FRIDAY AND SATURDAY AS SOUTHERLY LOW-LEVEL
FLOW RETURNS AND MID/UPPER FLOW BECOMES MORE SOUTHWESTERLY.

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&

$$

NWS GID Office Area Forecast Discussion