569
FXUS63 KOAX 061821
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
121 PM CDT MON APR 6 2026
KEY MESSAGES
- IMPACTFUL SNOW IS EXPECTED TONIGHT INTO TUESDAY MORNING WITH
2-4" ACCUMULATIONS LIKELY (70-80% CHANCE) WITHIN A NARROW
BAND. LOCALIZED 6" AMOUNTS ARE POSSIBLE (20-40% CHANCE).
EXPECT SOME AREA ROADS TO BECOME SLIPPERY/SNOW-COVERED,
SLOWING THE TUESDAY MORNING COMMUTE.
- AN ACTIVE WEATHER PATTERN WILL LEAD TO CONTINUED SHOWER AND
STORM CHANCES FROM WEDNESDAY THROUGH THE WEEKEND.
DISCUSSION
ISSUED AT 120 PM CDT MON APR 6 2026
REMAINDER OF THIS AFTERNOON THROUGH TUESDAY:
A VERY NARROW BAND OF LIGHT RAIN IS BEING OBSERVED AS OF EARLY
AFTERNOON ACROSS PORTIONS OF FAR NORTHEAST NE AND WEST-CENTRAL IA,
DRIVEN LARGELY BY THE RESPONSE TO FRONTOGENESIS IN THE 850-700-MB
LAYER, PER OBJECTIVE ANALYSIS. LATEST CAM DATA SUGGEST THAT BAND
WILL DRIFT SOUTHEAST THIS AFTERNOON INTO EVENING WITH ONLY LIGHT
PRECIPITATION AMOUNTS EXPECTED.
BY LATE THIS EVENING INTO THE OVERNIGHT HOURS, THE MODELS
INDICATE THE BROADENING AND INTENSIFICATION OF THE EXISTING
PRECIPITATION BAND, OWING TO STRENGTHENING FRONTOGENETICAL
FORCING AND DECREASING STATIC STABILITY. INITIAL PRECIPITATION
TYPE WOULD BE RAIN, WHICH THEN MIXES WITH SNOW BEFORE CHANGING
OVER TO ALL SNOW OVERNIGHT. UNCERTAINTY STILL EXISTS IN THE
EXACT PLACEMENT OF THE TWO TO THREE COUNTY-WIDE BAND WITH THE
CURRENT BEST GUESS OF A CENTERLINE EXTENDING FROM ATLANTIC, IA
TO BLAIR TO WEST POINT.
THE OVERALL SETUP IS RATHER IMPRESSIVE, FEATURING A DEEP LAYER OF
SATURATION AND UPWARD VERTICAL MOTION THAT EXTENDS INTO THE
DENTRITIC-GROWTH ZONE. MOREOVER, THERE ARE INDICATIONS OF WEAK
CONVECTIVE INSTABILITY ATOP OF THE MESOSCALE UPDRAFT, WHICH WOULD
ENHANCE SNOWFALL RATES. A FEW LIGHTNING STRIKES ARE EVEN
POSSIBLE. IN FACT, THE 12Z RUN OF THE HREF INDICATES A SEVERAL-
HOUR PERIOD BETWEEN ABOUT 1 AM AND 5 AM WHERE THERE IS A 50-70%
CHANCE LOCALIZED SNOW RATES OF AT LEAST 1"/HR. IN REGARD TO
AMOUNTS, THIS FORECAST UPDATE WILL INCREASE TOTALS TO 2-4"
WITHIN THE CENTER OF THE BAND (70-80% CHANCE) WITH LOCALIZED
AMOUNTS OF UP TO 6" APPEARING POSSIBLE (20-40% CHANCE).
GIVEN THE UNCERTAINTY IN EXACTLY WHERE THE SNOW BAND WILL SETUP, WE
HAVE DECIDED TO ISSUE A WINTER WEATHER ADVISORY FOR A BROADER AREA
FROM 10 PM TONIGHT UNTIL 1 PM TUESDAY. IF CONFIDENCE INCREASES IN
THE SNOWBAND LOCATION, AND THAT SOME HIGHER END AMOUNTS (6-8") ARE
LIKELY, THEN AN UPGRADE TO A WINTER STORM WARNING WOULD BE
CONSIDERED FOR A SMALLER AREA. THE MAIN IMPACT WILL BE TO ROADS,
WHICH ARE EXPECTED TO BECOME SLIPPERY/SNOW-COVERED IN AREAS OF
THE HIGHEST SNOW RATES. PLAN FOR SLOWER COMMUTE TIMES TUESDAY
MORNING.
TEMPERATURES WILL STRUGGLE TO GET OUT OF THE 30S ON TUESDAY IN AREAS
THAT RECEIVE THE HIGHER SNOWFALL AMOUNTS WITH 40S AND 50S EXPECTED
ELSEWHERE.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT:
A VIGOROUS, MID/UPPER-LEVEL LOW WILL MOVE ALONG THE U.S./CANADIAN
BORDER THIS PERIOD WITH AN ASSOCIATED COLD FRONT MOVING INTO THE
AREA WEDNESDAY BEFORE STALLING. WARM ADVECTION AND MOISTURE
TRANSPORT OCCURRING ALONG A 50+ MPH LOW-LEVEL JET WILL RESULT IN
WEAK AIR MASS DESTABILIZATION WITHIN THE PRE-FRONTAL WARM SECTOR.
THOSE PROCESSES WILL SUPPORT INCREASING SHOWER AND ISOLATED
THUNDERSTORM CHANCES, ESPECIALLY WEDNESDAY AFTERNOON INTO WEDNESDAY
NIGHT (MAXIMUM POPS OF 40-60%).
SOME DOWNWARD MIXING OF THE LOW-LEVEL JUST WILL LEAD TO WINDY
CONDITIONS WEDNESDAY WITH GUSTS UP TO 35 MPH. IT NOW APPEARS
THAT THE ATMOSPHERE MAY END UP A LITTLE MORE MOIST WITH MORE
CLOUD COVER, LIMITING FIRE DANGER TO THE HIGH CATEGORY IN
NORTHEAST NE. HIGH TEMPERATURES ARE EXPECTED TO BE IN THE 60S TO
LOW 70S.
THURSDAY AND FRIDAY:
THE GLOBAL MODELS CONTINUE TO INDICATE A LOW-AMPLITUDE DISTURBANCE
MOVING THROUGH THE NORTHERN PLAINS THURSDAY INTO THURSDAY NIGHT. THE
GLANCING INFLUENCE OF THAT FEATURE COUPLED WITH STRENGTHENING LOW-
LEVEL CONVERGENCE AND WARM ADVECTION ALONG TO THE NORTH OF THE
FRONTAL SYSTEM STALLED ACROSS THE AREA WILL RESULT IN A GOOD CHANCE
(40-80% POPS) OF SHOWERS AND A FEW THUNDERSTORMS, ESPECIALLY
ACROSS THE SOUTHERN HALF OF THE AREA.
THERE IS SOME MODEL SIGNAL THAT THE FRONT MAY BE TEMPORARILY BE
PUSHED SOUTH OF THE AREA ON FRIDAY. THE CURRENT FORECAST WILL
MAINTAIN 20-50% POPS.
HIGHS IN THE 50S AND 60S ARE FORECAST BOTH DAYS.
SATURDAY AND SUNDAY:
THE ENSEMBLE AND DETERMINISTIC MODELS ALL INDICATE THE MOVEMENT OF A
LARGE-SCALE TROUGH ONTO THE WEST COAST THIS PERIOD; HOWEVER,
THERE ARE CONSIDERABLE DIFFERENCES IN THE STRUCTURE OF THE
BROADER TROUGH, AND THE MOVEMENT OF EMBEDDED VORTICITY MAXIMA.
DESPITE THESE DIFFERENCES, SURFACE LEE TROUGHING IS EXPECTED TO
DEEPEN ALONG THE HIGH PLAINS, WHICH IN TURN WILL ENHANCE THE
POLEWARD FLUX OF INCREASING MOISTURE CONTENT THROUGH THE GREAT
PLAINS. THE MOISTURE RETURN WILL CONTRIBUTE TO AN UNSTABLE AIR
MASS, WHICH COMBINED WITH FORCING FOR ASCENT ASSOCIATED WITH ANY
WEAK DISTURBANCES EJECTING OUT OF THE WESTERN U.S. TROUGH, WILL
SUPPORT CONTINUED SHOWER AND THUNDERSTORM CHANCES. THE VARIOUS
MACHINE-LEARNING MODELS INDICATE SOME SEVERE WEATHER POTENTIAL
(5-10% CHANCE) AT THIS TIME.
TEMPERATURES ARE EXPECTED TO TREND WARMER WITH HIGHS IN THE 60S AND
70S.
AVIATION /18Z TAFS THROUGH 18Z TUESDAY/
ISSUED AT 1215 PM CDT MON APR 6 2026
VFR CONDITIONS START OUT THE TAF PERIOD, WITH SOME LOWER CLOUDS
AT FL035 SNEAKING IN NEAR KOFK AND POINTS TO THE NORTHWEST.
WINDS WILL BE OUT OF THE NORTHEAST THROUGH THE EVENING, BECOMING
MORE EASTERLY OVER TIME WITH PERIODIC GUSTS OF 15-20 KTS WHERE
SOME PEEKS OF SUNSHINE OCCUR. THE MAIN CONCERN OF THE NEXT 24
HOURS IS THE DEVELOPMENT OF A NARROW SNOW BAND THAT IS CURRENTLY
FORECAST TO AFFECT KOFK AND KOMA, WITH KLNK CURRENTLY IN THE
CLEAR. THE LATEST MODEL DATA IS STILL COMING TOGETHER IN TERMS
OF A MORE CONSISTENT PLACEMENT OF SNOW, BUT THIS NARROW BAND
WILL BE SET TO RAMP UP 05-07Z, BRINGING IFR TO LIFR CONDITIONS
TO KOFK AND KOMA BEFORE DISSIPATING AND SLOWLY SHIFTING
NORTHEAST BY 11-13Z. VISIBILITIES WILL QUICKLY DROP ONCE IT GETS
GOING, WITH THERE BEING SOME POTENTIAL FOR DROPS DOWN TO 1/4 OF
A MILE. OVERALL SNOW CHARACTER WILL BE WET AND HEAVY, AND IT
WILL LEAVE BEHIND CEILING RESTRICTIONS IN THE IFR TO MVFR
TERRITORY THROUGH 18Z TOMORROW AT ALL THREE TERMINALS.
OAX WATCHES/WARNINGS/ADVISORIES
NE...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 1 PM CDT
TUESDAY FOR NEZ033-034-044-045-051>053.
IA...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 1 PM CDT
TUESDAY FOR IAZ055-056-069-079-080.
DISCUSSION...MEAD
AVIATION...PETERSEN
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