####018006327#### FXUS62 KCHS 092055 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 455 PM EDT Thu May 9 2024 .SYNOPSIS... A cold front will approach the area tonight, then move offshore Friday. High pressure will prevail for the weekend into early next week. A storm system could affect the area by the middle of next week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Radar indicates the line of strong thunderstorms has moved off our coast and the severe threat has come to an end. The tornado watch has been dropped. Though, we expect another 1-2 hours of stratiform precipitation for some locations, especially along the coast, followed by clearing this evening. The rest of the night should be dry. However, a second MCS will arrive from the west after the pre-dawn hours Friday morning. Temperatures are expected to remain nearly steady around 70 degrees tonight. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... The forecast for Friday is quite tricky. A quasi-zonal flow will persist aloft, though we will see several potent shortwaves ripple through the area during the day. Given the high theta-e airmass across the Southeast, ample instability should be in place to support convective development with these upper vort maxima. Furthermore, the presence of 50-60 kt of 0-6 km bulk shear will favor organization of the convection once it become established. Most of the guidance continues to indicate the most impressive shortwave will move through southeast SC/GA between 15Z and 18Z. There is surprising agreement between the synoptic models and the CAMs that a large area of showers and thunderstorms will move across the forecast area between 9am and 3pm Friday. It appears that an MCS could be ongoing across south central GA at daybreak that then pushes east through our area. Thus, the greatest coverage of convection would occur over our southeast GA zones. This is also where the strongest convective indices are expected, so our primary focus for severe weather potential is in southeast GA and extreme southern SC. Damaging winds appear to be the primary threat assuming the convection becomes organized into a line. Isolated large hail or tornadoes can never be completely ruled out. Farther to the north in SC, at least scattered showers and thunderstorms will move through, but extensive cloud cover in the morning and less available instability should reduce the overall severe weather potential. Rainfall totals on Friday will range from 1-1.5" in southeast GA and 0.5-1.0" in southeast SC. The brunt of the convection is expected to be off the coast by 3pm. A secondary shortwave will drop into SC early Friday evening, pushing the cold front into the area. A big question mark is what convection, if any, develops out ahead of the front. It will heavily depend on what happens in southern SC with the first batch of convection and whether or not the airmass gets worked-over as a result. If convective coverage is limited during the early afternoon activity, a greater degree of destabilization could occur in southern SC, allowing for a more conducive airmass for convective development late Friday afternoon or early evening. For now we penciled in scattered PoPs across eastern Berkeley/Charleston Counties late afternoon and early evening. Saturday will be dry and noticeably cooler with highs in the upper 70s. Sunday will warm up a bit due to upper ridging, with highs in the mid 80s. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Early next week will briefly start off quiet before a warm front extending across the Deep South lifts north. Conditions look quite unsettled beginning late Monday night into Wednesday due to plentiful upper forcing and deep moisture building in. Several rounds of showers and thunderstorms are expected. && .AVIATION /21Z THURSDAY THROUGH TUESDAY/... 21z TAFs: Radar indicates the line of strong thunderstorms has moved east of all of the TAF sites, so they were amended to show the improving conditions. Behind the storms, stratiform precipitation will persist until early evening, then end. VFR is expected for part of the night. MOS and some of the ensembles then indicate IFR ceilings developing over the terminals late tonight, which we have in the TAFs. Finally, another round of showers and thunderstorms is expected to bring impacts to the TAF sites late in the TAF time period. Extended Aviation Outlook: Scattered to numerous showers and thunderstorms could continue into Friday afternoon with flight restrictions and gusty winds possible within convection. VFR conditions will return for the weekend into early next week. Scattered convection expected Monday night and Tuesday. && .MARINE... Through Sunset: A line of thunderstorms is moving though the coastal waters. Some of these storms could produce gusts in excess of 40 kts and possibly a waterspout. The main line of storms should move east our waters and dissipate by about sunset. Tonight: Expect winds to be mainly SW 10-20 kt. A few gusts up to 25 kt are possible across the Charleston County waters this evening, especially across the far northeastern portion of the zone. But the time and areal extend don't appear to be enough to warrant a Small Craft Advisory. Seas should be in the 2-4 ft range. Friday: A decent SW gradient expected in advance of a cold front, though winds will be quite variable once convection moves offshore midday. Late in the afternoon and early evening, wind gusts could approach 25 kt, so it's not out of the realm of possibility that a short-duration Small Craft Advisory is needed. Due to the low confidence we will hold off on any issuance with this package. Marine conditions will improve Saturday morning as high pressure builds in from the west. Winds/seas expected to increase Monday night into Tuesday ahead of the next storm system. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM...JRL LONG TERM...JRL AVIATION...JRL MARINE...JRL ####018003222#### FXUS63 KGID 092058 AFDGID Area Forecast Discussion National Weather Service Hastings NE 358 PM CDT Thu May 9 2024 .KEY MESSAGES... - below-normal precipitation totals are favored through the next 1-2 weeks. - Only spotty showers and perhaps a stray thunderstorm are expected through this evening. Nearly the entire area will stay dry. - Better chances for thunderstorms Sunday and Monday. The threat for severe weather appears to be fairly low. && .DISCUSSION... Issued at 400 PM CDT Thu May 9 2024 Visible satellite shows pretty extensive cumulus development this afternoon, and the regional radar mosaic shows a few returns over northern Nebraska gradually moving southward. These isolated showers may reach northern portions of the area late this afternoon before gradually diminishing in the evening with loss of diurnal heating. There is enough instability (100J/kg) for a rumble of thunder or two, but severe weather is not expected. If anything, the latest runs of near-term models are even less impressed with the coverage/intensity of this activity reaching into our area. Nearly everyone will stay dry, and even areas that do see rain likely will not see more than 0.05". The pattern remains stagnant on Friday, with continued northwesterly surface winds and temperatures only a few degrees warmer than today. A cutoff upper low will remain stalled over the western CONUS as another shortwave skirts by to our northwest Friday evening. Another round of spotty showers cannot be ruled out, but the probability/impact is too low to add anything into the forecast at this point. The daytime of Saturday will be warm, dry and pleasant, but the aforementioned upper low will slowly begin to break down down and eject into the central Plains late Saturday night into Sunday. This will bring us a chance for scattered showers and thunderstorms, especially Sunday afternoon into the evening. That said, deep-layer shear is expected to be quite limited, so the overall threat for severe weather remains pretty low. Highest rain totals favor portions of Kansas, but exact details remain quite uncertain. Some activity could redevelop as this system slowly departs the area on Monday, and additional chances for rain and storms arrive with another shortwave trough Tuesday into Wednesday. Despite all of these rain chances, global ensembles all show near to below-normal precipitation totals through the end of next week. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 1209 PM CDT Thu May 9 2024 Expect northwesterly winds through the period. Afternoon winds are expected to gust into the low 20s today and tomorrow. Only the NAM has the 025-030 cloud layer moving into the TAF sites this afternoon. Upstream is showing BKN-OVC, but satellite trends shows the clouds thinning as they move south. Decided to put a SCT030 layer for now and will watch and see how the clouds evolve this afternoon. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ DISCUSSION...Mangels AVIATION...Beda