Sunrise 6:47 AM   Sunset 8:22 PM Moonrise 4:29 PM   Moonset 4:34 AM

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FXUS63 KGID 201142 AFDGID

Area Forecast Discussion National Weather Service Hastings NE 642 AM CDT Sat Apr 20 2024

KEY MESSAGES

- Cool and cloudy again today with 20-50% chance for light rain/snow through the daytime hours, mainly SW of the Tri- Cities. <20% chance for total moisture >0.10".

- Another round of near to below freezing temperatures tonight.
50-90% chance along/N of state line, 20-60% chance for N KS.
Additional frost/freeze headlines are likely tonight-Sun AM.

- Nicer weather returns for Sunday afternoon. Generally near to above normal temperatures for the upcoming work week with mainly 60s and 70s for highs, and lows mostly above mid 30s.

- Rain chances return Mon PM (20-50% chance). Fairly active pattern mid to late week with overall greatest chances coming Wed night through Thu night (40-60%). The storms on Thu will need to be monitored for severe potential, esp. across KS.

DISCUSSION
Issued at 515 AM CDT Sat Apr 20 2024

No major changes to the forecast this cycle.

Still looking at another cool and cloudy day today thanks to weak upper disturbance and lift from RER of upper jet streak.
Best combination of lift and deeper moisture will focus SW of the Tri-Cities today, particularly for areas from around Cambridge to Phillipsburg where chances peak at around 50%.
However, even these areas will likely only receive very light amounts as latest NBM gives <20% chance for total moisture more than a tenth of a inch. Highs will likely be limited to upper 40s to lower 50s thanks to the persistent cloud cover, but at least the Nrly winds will be fairly light at 5-15 MPH. See no reason to adjust ongoing Freeze Warning as clouds have stabilized temps along and S of the state line. Further N, some clearing overnight allowed temps to fall further into the 30s and even upper 20s, and areas N of I-80 are still clear and could fall further into mid 20s by dawn.

Model consensus is for gradually clearing skies tonight, esp.
after midnight, for all but perhaps far W/SW zones. Fairly lgt winds brought about by sfc ridging, along with dew points in the 20s, should allow for a more widespread freeze Sat night into Sun AM. Plan once again is to allow ongoing headline to expire and let day shift reissue for tonight, likely further S to at least the state line. KS zones, esp further S tier, may be able to get by with a Frost Advisory, though the 20s dew points could keep even this on the limited side. High temps Sun aftn will still likely be below normal in the upper 50s to lower 60s, but it will feel pretty nice given copious sunshine and only lgt SWrly winds around 5-10 MPH. Strengthening return S flow will not only keep low temps above freezing Sun night, but also lead to warmer highs on Mon in the 70s, perhaps even low 80s far SW.

Next decent chance (up to ~50%) will come with a cold front Mon eve into overnight. Severe weather is not expected at this time, but a few strong storms with small hail can't be ruled out given MUCAPE expected to rise to around 500 J/kg amidst strong effective deep layer shear values in excess of 40kt and freezing levels only 8-9k ft. Will also see some lift from 40-50kt LLJ that at least briefly noses into the area 00Z-06Z before shifting E/SE. Should be dry by Tue AM with brzy N winds working to keep highs a bit cooler in the 60s to near 70F. Return flow could lead to some low end pcpn chcs Tue night into Wed, but otherwise expect highs in the 60s to low 70s and brzy SE winds.

Thunderstorm chances increase (30-50%) Wed night into Thu AM with even stronger LLJ/warm/moisture advection in response to an upper trough shifting E over the Four Corners region. High temperatures on Thursday are expected to be a little warmer than Wed, especially over KS zones, thanks to closer proximity to potential surface warm front. Exact timing of shortwave ejection onto the Plains, and location of pertinent sfc features such as sfc low and associated fronts...remains a bit uncertain and will be key to determining overall severe storm potential.
General consensus is that highest rain/storm chances will come Thu eve/night (50-60%) with primary upper shortwave and incipient warm air/moisture advection and convergence on nose of LLJ. Consensus also suggests that best instability could be confined to S Plains into KS, E of the dry line and S of the warm front, where deep layer shear will be in excess of 40kt and more than sufficient for severe convection. It will take some time for airmass recovery over the NW Gulf of Mexico thanks to early week frontal passage, so moisture return could be a bit delayed - which also supports greater risk over KS than NE.
However, a slower ejection of the upper shortwave, which is certainly possible if overall amplitude increases (as latest deterministic EC hints at), could allow for more time for moisture return, and even bring severe weather potential further N and on Fri into play. As it stands now, appears the sfc low will progress far enough E to keep greatest severe weather potential over mid to lower MO Valley on Fri. This general evolution is displayed well in the latest SPC Day 6 and Day 7 outlooks, though as we saw earlier this week, adjustments are certainly possible as we get closer. Temps look to decline a bit into next weekend behind the departing storm system.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
Issued at 640 AM CDT Sat Apr 20 2024

VFR expected through the period.

Today: Incr mid to high clds forecast through the AM, with much of the daytime hrs seeing BKN-OVC skies with CIGs around 8-12k ft. Can't rule out some sprinkles or very lgt shwrs in the EAR area this aftn. Winds will vary a bit in direction, but generally remain NW to WNW around 6-10kt. Confidence: High.

Tonight: Decr clouds in the 03Z-06Z time frame to SKC. Lgt W to NW winds 5-8kt. Confidence: High.

GID WATCHES/WARNINGS/ADVISORIES
NE...Freeze Warning until 8 AM CDT this morning for NEZ039>041- 046>049-060>064-072>077.
KS...None.

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