897
FXUS63 KGRB 050236
AFDGRB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREEN BAY WI
936 PM CDT SAT APR 4 2020
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
SHORT TERM
TONIGHT AND SUNDAY
ISSUED AT 237 PM CDT SAT APR 4 2020
THE SHORT TERM WILL BE A FAIRLY QUIET PERIOD WEATHER WISE AS HIGH
PRESSURE PERSISTS. THE MAIN FOCUS WILL BE LOW TEMPERATURES
TONIGHT.
TONIGHT, IDEAL COOLING CONDITIONS ARE EXPECTED ACROSS THE REGION,
ESPECIALLY ACROSS NORTHERN WISCONSIN. DRY AIR, CALM WINDS, AND
CLEAR SKIES WILL BRING TEMPERATURES DOWN QUICKLY, ESPECIALLY IN
OUR TYPICAL COLD SPOTS ACROSS THE FAR NORTH WHERE WE ALSO HAVE A
LINGERING SNOWPACK. LOW TEMPERATURES IN THE NORTH WILL BE IN THE
TEENS, POSSIBLY EVEN DROPPING BRIEFLY INTO THE SINGLE DIGITS
BEFORE SUNRISE. TEMPERATURES ELSEWHERE WILL REMAIN IN THE 20S.
SUNDAY WILL BE BRIGHT AND SUNNY, WITH TEMPERATURES RECOVERING
QUICKLY FROM THE OVERNIGHT HOURS, ESPECIALLY NEAR THE FOX VALLEY
WHICH WILL HAVE A WARMER START. KEPT TEMPERATURES TOWARDS THE
HIGHER END OF GUIDANCE, WITH HIGHS IN THE LOWER TO MIDDLE 50S.
LONG TERM
SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 237 PM CDT SAT APR 4 2020
PRIMARY FOCUS IS ON THE TUESDAY/TUESDAY EVENING TIME FRAME, WHEN
THERE IS POTENTIAL FOR WIDESPREAD SHOWERS AND THUNDERSTORMS, AND
POSSIBLY SOME SEVERE WEATHER IN THE SOUTHERN PART OF THE CWA.
EXPECT GENERALLY DRY CONDITIONS ON SUNDAY NIGHT, AS HIGH PRESSURE
CONTINUES TO SHIFT EAST THROUGH THE GREAT LAKES REGION.
DEVELOPING RETURN FLOW AND H8 WAA WILL BRING A CHANCE OF SHOWERS
TO THE REGION MONDAY INTO MONDAY NIGHT. THE GFS IS MOST AGGRESSIVE
WITH THIS, AND HAS TWO SEPARATE BANDS OF RAIN, ONE OVER THE FAR
NORTH AND ANOTHER OVER CENTRAL AND EAST CENTRAL WI. KEPT POPS IN
THE CHANCE CATEGORY FOR NOW. WEAK ELEVATED INSTABILITY WILL WORK
IT'S WAY INTO THE SOUTHWEST PART OF THE FORECAST AREA, LEADING TO
THE POTENTIAL FOR ISOLATED THUNDERSTORMS.
MODELS SHOW A CLIPPER-LIKE SYSTEM IN ZONAL FLOW MOVING THROUGH WI
ON TUESDAY AND TUESDAY EVENING. IT IS POSSIBLE THE LOW MAY TRACK
FAR ENOUGH NORTH TO ALLOW THE WARM FRONT TO LIFT INTO CENTRAL AND
EAST CENTRAL WI. THIS SYSTEM WILL BE AIDED BY UPPER DIVERGENCE
FROM COUPLED UPPER JETS AND A SHORT-WAVE TROF (LATE AFTERNOON AND
EVENING). DEEP LAYER SHEAR IS QUITE STRONG (45-55 KTS) AND 0-3 KM
SRH IS 200-400. MUCAPE IS FORECAST TO REACH 1000-1500 J/KG IN
CENTRAL AND EAST CENTRAL WI, AND 700-500 MB LAPSE RATES ARE
EXPECTED TO BE 7.5-8 C/KM. INGREDIENTS ARE IN PLACE FOR A POSSIBLE
SEVERE EVENT, BUT CONFIDENCE IS STILL LOW GIVEN THE POTENTIAL FOR
THE FRONT TO STAY FARTHER SOUTH THAN ANTICIPATED, AND EXPECTED
CLOUD COVER/LACK OF INSOLATION. TOOK A QUICK LOOK AT CIPS ANALOGS,
AND THEY VALIDATED THE POTENTIAL FOR AT LEAST A MARGINAL SEVERE
EVENT IN CENTRAL AND EAST CENTRAL WI. WILL BEEF UP THE WORDING IN
THE HAZARDOUS WEATHER OUTLOOK. HIGHS WILL BE MUCH ABOVE NORMAL,
RANGING FROM THE UPPER 40S TO MIDDLE 50S NORTHEAST, TO THE MIDDLE
TO UPPER 60S SOUTHWEST.
A COLD FRONT WILL MOVE THROUGH THE REGION ON WEDNESDAY AND
WEDNESDAY EVENING, BRINGING ANOTHER CHANCE OF SHOWERS, FOLLOWED BY
GUSTY WINDS AND COOLER TEMPERATURES INTO THURSDAY.
COOL BUT GENERALLY DRY WEATHER IS ANTICIPATED LATE IN THE WEEK,
WITH WEAK RIDGING AT THE SURFACE AND ALOFT ARRIVING BY SATURDAY.
AVIATION
FOR 06Z TAF ISSUANCE
ISSUED AT 936 PM CDT SAT APR 4 2020
DRY HIGH PRESSURE BUILDING ACROSS THE AREA WILL ALLOW FOR GOOD
FLYING CONDITIONS THROUGH MOST OF THIS TAF PERIOD. THE EXCEPTION
WILL BE THE EASTERN TAF SITES, WHERE SOME LOW CLOUDS HAVE FORMED
WITH LIGHT FLOW OFF LAKE MICHIGAN. CEILINGS HAVE GENERALLY DROPPED
TO AROUND 800FT WITH THE ONSHORE/UPSLOPE FLOW AND WILL LIKELY
LINGER THROUGH THE NIGHT AS THEY EXPAND WESTWARD. THE LOW CLOUDS
AT MTW WILL EXPAND TO GRB AND ATW BETWEEN 03Z AND 04Z. LIGHT AND
VARIABLE WINDS ARE EXPECTED.
GRB WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM.....UHLMANN
LONG TERM......KIECKBUSCH
AVIATION.......COOLEY
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