Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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537 FXUS62 KRAH 230103 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 903 PM EDT Sat Jun 22 2024 .SYNOPSIS... A weak mid and upper-level trough will move across the Middle Atlantic Sunday and Sunday night. A stronger trough and accompanying surface cold front will move across NC Monday and Monday night. The front will then weaken and dissipate over the Carolinas through mid- week. && .NEAR TERM /THROUGH TONIGHT/... As of 900 PM Saturday... No major changes with the evening update. The 00Z upper air analyses show the 593 dam H5 high over the southern Plains, with central NC still on the eastern periphery of the high. There is still a bit of dry air over central NC at H7, but still moist at H85. The 00Z surface analysis shows a weak trough over the NC Piedmont, between a high over the NC mountains to the west and Bermuda high to the east. Surface dewpoints have rebounded a bit back into the upper 60s to mid 70s, with the exception of a few lingering mid 60s along the VA border. Still expect lows to bottom out in the low/mid 70s, making for another muggy night across central NC. There are a few lingering showers over Anson county as of 9 PM, but those are expected to dissipate over the next couple of hours. The remainder of the night should be dry. Still expect development of low stratus again tonight, mainly across the southeast half of central NC. && .SHORT TERM /SUNDAY AND SUNDAY NIGHT/... As of 250 PM Saturday... Heights at 500mb will lower by 20-40m on Sunday as a shortwave crossing the northern US dips into a weakness in the upper ridge, with an associated cold front approaching the region Sunday night. Ahead of the front, the remnants of AL92 near Savannah today will begin to drift north in a further weakened state and become absorbed into the upper trough, with broad sw-rly flow across the region. That warm sw-rly flow should offset the slight weakening of the ridge and keep temps similar to today in the mid 90s. Soundings also once again suggest decent mixing and dewpoints in the upper 60s to lower 70s, which keeps heat indices in the 100-104 range in the east where heat advisory concerns would be greatest. Even if a few sites hit 105, a modest 10kt wind with occasional gusts to 15-20kt should also keep the heat from feeling overly oppressive, and wet bulb globe temps remain in mostly in the 84-86 range, suggesting only a moderate heat threat. Based on this and coordination with neighboring offices, we are not issuing a Heat Advisory at this time. Isolated to widely scattered showers are possible across mainly the southern coastal plain associated with enhanced seabreeze and perhaps the weakening AL92 circulation during the afternoon and evening. Northern areas are initially capped but with heights aloft lowering there should be a weakening line of storms associated with a pre-frontal trough late in the evening. Poor diurnal timing will limit any severe threat. Given how dry forecasting soundings are, coverage should not be very high in either area., but individual showers and storms will produce gusty winds with high DCAPE and inverted V profiles. Overnight lows will be very muggy in the low to mid 70s. && .LONG TERM /MONDAY THROUGH SATURDAY/... As of 330 PM Saturday... A long stretch of hot temperatures, ~5-10 F above average and in the 90s, will result throughout the forecast period, though seasonable to seasonably low surface dewpoints/humidity values will regulate/temper Heat Index values until at least Wed. A nrn stream shortwave trough/compact closed cyclone now centered over srn Saskatchewan will amplify modestly while progressing sewd and across the Great Lakes through this weekend, then across and offshore the Middle Atlantic Mon-Mon night. Glancing and weak (10-20 m/12 hr) mid-level height falls, and the passage of a surface cold front, will result over cntl and ern on Mon. Scattered convection will accompany the front, with the relative greatest concentration from the Coastal Plain to the coast. Shortwave ridging and marked mid-level drying and warming will follow and expand across the srn Appalachians and Carolinas Tue-Tue night, during which time weak high pressure and dry but still hot conditions will build across the srn Middle Atlantic. A couple of additional shortwave perturbations are otherwise forecast to migrate ewd and across the Canada/US international border and Great Lakes mid-late week and support an associated weak cold frontal passage across the srn Middle Atlantic late Thu-early Fri. Low-level moisture/humidity will increase ahead of the front and favor a renewed, ~30-50% chance of diurnal convection Wed and especially Thu. A broad and strong mid-level high/ridge will then restrengthen from the srn Plains and Southeast to the w-cntl Atlantic through next weekend. A related surface high will expand from the cntl Atlantic, near and east of Bermuda, wwd and across the South Atlantic states, while an Appalachian-lee trough will extend across the srn Middle Atlantic Foothills/wrn Piedmont. The presence of the ridge and warming aloft should tend to keep the chance of diurnal convection near or slightly below climo probabilities (~20-30%). && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... As of 714 PM Saturday... Through 00Z Monday: The primary aviation concern through the 24 hour TAF period will be the chance for a period of low-MVFR or IFR cigs mainly along and south of a line from KIXA-KRDU-KVUJ between 08z-13Z Sunday. Otherwise, VFR conditions are expected with S to SW winds generally around 10kt, with a few higher gusts to 15- 20kt after 13Z Sunday. After 00Z Monday: An approaching cold front will support a slight chance of showers and storms and related sub-VFR restrictions late Sunday, with better coverage on Monday. Tuesday should be mostly dry before isolated showers and storms may return on Wednesday especially west. && .CLIMATE... Record High Temperatures: June 22: KRDU: 100/2022 KFAY: 101/2022 June 23: KRDU: 100/1986 June 24: KRDU: 99/2010 KFAY: 102/1914 June 25: KRDU: 100/1952 KFAY: 102/1914 June 26: KRDU: 102/1952 KFAY: 101/1951 June 27: KFAY: 102/1998 Record High Minimum Temperatures: June 22: KRDU: 78/1933 June 23: KGSO: 74/2015 KRDU: 77/1890 KFAY: 77/2017 June 24: KGSO: 76/2015 KRDU: 76/1888 KFAY: 79/2010 June 25: KFAY: 75/1952 June 26: KGSO: 74/2010 KRDU: 76/1902 KFAY: 76/1997 June 27: KGSO: 76/1969 KRDU: 76/1952 KFAY: 77/1998 June 28: KGSO: 76/1969 KRDU: 76/1952 KFAY: 78/1914 && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...MWS NEAR TERM...KC SHORT TERM...bls LONG TERM...MWS AVIATION...pwb/np CLIMATE...RAH