FXUS63 KOAX 170817
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
317 AM CDT WED AUG 17 2011
.DISCUSSION...
ACTIVE FLOW ON THE NORTHERN SIDE OF AN UPPER-LEVEL HIGH WILL KEEP
THE AREA IN CHANCES FOR INTERMITTENT SHOWERS AND THUNDERSTORMS
THROUGH THE NEXT SEVERAL DAYS. SUBJECTIVE 00Z UPPER AIR ANALYSIS
INDICATES UPPER HIGH CENTERED IN AZ/NM...WITH WEAK RIDGING EXTENDING
INTO THE MID-MISSOURI RIVER VALLEY. UPPER LOW WAS MOVING ACROSS
CANADA...CENTERED IN CENTRAL MB WITH 500MB HEIGHT FALLS EXTENDING
INTO THE NORTHERN GREAT LAKES. FLOW ACROSS THE CENTRAL AND NORTHERN
PLAINS WAS MAINLY ZONAL...WITH WEAK RIPPLE NOTED IN WY AT 00Z THAT
HAD REACHED NEB BY 07Z. 850MB LOW AT 00Z WAS CENTERED IN CENTRAL
MB...WITH FRONT EXTENDING THROUGH MN AND ACROSS THE MID-MISSOURI
RIVER VALLEY INTO KS AND BACK TOWARD AZ. MOISTURE HAD POOLED ALONG
THE FRONT...WITH 16C DEWPOINT NOTED AT KOAX AND 17C AT KTOP...AND
WITH AXIS OF 12C+ DEWPOINT EXTENDING FROM THE GULF COAST INTO ONT.
SURFACE HIGH AT 07Z WAS CENTERED IN SD...BEHIND A WEAK FRONT
EXTENDING FROM EASTERN MN THROUGH WESTERN IA. A FEW CLOUDS WERE
NOTED ALONG AND BEHIND THE FRONT...BUT CONVECTION AT 07Z WAS LIMITED
TO WESTERN KS/EASTERN CO.
MAIN FORECAST CONCERN IS INTERMITTENT CHANCES OF THUNDERSTORMS
TONIGHT THROUGH SATURDAY. THINK TODAY SHOULD BE QUIET AS HIGH
PRESSURE/MID-LEVEL RIDGE SLIDE ACROSS THE AREA. CONVECTION SHOULD
DEVELOP TODAY ON THE HIGH PLAINS...AND MODELS ARE IN PRETTY GOOD
AGREEMENT THAT IT WILL GROW UPSCALE INTO AN MCS THAT REACHES EASTERN
NEB BY 12Z. MODELS THEN KEEP PRECIP AROUND THE AREA THROUGH THE
SUBSEQUENT 24 HOURS...WHICH IS A SCENARIO THAT IS LESS CONFIDENT. A
VORT MAX SHOULD MOVE THROUGH EASTERN NEB IN THAT TIME...BUT NOT SURE
THAT CAN SUSTAIN CONVECTION OVER THE CWA FOR 24 STRAIGHT HOURS.
HAVE KEPT POPS IN ALL PERIODS FROM TONIGHT THROUGH THURSDAY
NIGHT...WITH A SHORT BREAK ACROSS MOST OF THE AREA ON FRIDAY...BUT
WOULD NOT BE SURPRISED BY DRY PERIODS BETWEEN TONIGHT AND THURSDAY
NIGHT. HAVE MODERATED TEMPS A BIT IN THIS PERIOD THOUGH...AS
LINGERING CLOUDS COULD HOLD TEMPS DOWN A BIT DURING THE DAY AND UP A
BIT AT NIGHT.
BY THE END OF THE WORK WEEK...AN UPPER TROUGH IS PROGGED TO MOVE
ACROSS SOUTHERN CANADA...BRINGING A PUSH OF COOLER AIR INTO THE
PLAINS. AS BOUNDARY PUSHES ACROSS THE DAKOTAS/MN INTO
NEB/IA...CONFIDENCE IS PRETTY HIGH IN WIDESPREAD SHOWERS AND THUNDER
FRIDAY NIGHT INTO SATURDAY...INCLUDING SOME POTENTIAL FOR SEVERE
STORMS AND HEAVY RAIN. HAVE INCREASED POPS AND QPF IN THAT TIME.
BEHIND THE BOUNDARY...TEMPS SHOULD COOL AS 850MB TEMPS FALL INTO THE
LOW TEENS AND HIGH PRESSURE SLIDES ACROSS THE PLAINS. HAVE BROUGHT
HIGH TEMPERATURES DOWN OVER THE WEEKEND TO REFLECT THIS COOLING
TREND...ESPECIALLY ON SATURDAY. NORTHWEST FLOW IS PROGGED TO
DEVELOP INTO EARLY NEXT WEEK AS UPPER HIGH STRENGTHENS OVER
NM/CO...WITH UPPER LOW DEEPENING IN EASTERN CANADA/NEW ENGLAND.
MODELS ARE GENERALLY QUIET THROUGH MIDWEEK...WITH QUITE A BIT OF
DIFFERENCE AMONG MODELS REGARDING ANY CHANCES FOR PRECIP.
MAYES
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z ISSUANCE.
PRIMARY FORECAST CONCERN WILL BE FOG AND LOW CIGS THROUGH THE EARLY
MORNING HOURS.
MVFR TO OCCASIONAL IFR FOG HAS MOVED INTO THE TERMINALS EARLY THIS
MORNING...ALONG WITH A FEW AREAS OF IFR STRATUS. MVFR TO OCCASIONAL
IFR CONDITIONS CAN BE EXPECTED UNTIL AFTER SUNRISE THIS MORNING AT
THE TAF SITES.
ANY REMAINING STRATUS AND FOG WILL LIFT AFTER SUNRISE...WITH HIGH
PRESSURE BUILDING OVER THE AREA. LIGHT WINDS AND VFR CONDITIONS ARE
EXPECTED FOR THE REMAINDER OF THE TAF PERIOD.
BOXELL
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$