Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
Issued by NWS Raleigh/Durham, NC
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492 FXUS62 KRAH 140737 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 333 AM EDT Sun Jul 1342024 .SYNOPSIS... A strong subtropical ridge will remain over the Southeast through early to mid-week. && .NEAR TERM /THROUGH TONIGHT/... As of 330 AM Sunday... ...A Heat Advisory Has Been Issued for portions of the Central Piedmont, Sandhills, and Coastal Plain Counties... A flat but strong upper ridge over the SE US coupled with Bermuda surface high pressure will result in hot and humid conditions over the next several days. Meanwhile, the lingering sfc front will wash out into a lee troughing along the eastern slopes of the Appalachians. The heat returns in strong fashion today as H8 temps are forecast to warm from 19 to ~22 C this afternoon, with similarly impressive increase in low-level thicknesses from 1432m to ~1442m. Afternoon highs are expected to warm into the mid to upper 90s. A weak/light westerly downslope component will aide in mixing dewpoints down into the 60s across the western Piedmont, which will help to mitigate the heat risk. However, dewpoints across the remainder of the area will consist in the lower to mid 70s, yielding heat indices of 104 to 109 degrees across the Central Piedmont, Sandhills, and Coastal Plain counties. In coordination with our eastern neighboring NWS offices, will issue a Heat Advisory that will go in effect at 11 am and continue through 7pm. In terms of rain chances, a very weak, low-amplitude shortwave will traverse the mid-Atlantic region during the afternoon and early evening. Weak lift from this feature, as well as the lee side sfc trough, amidst very steep low-level lapse rates, will support isolated to widely scattered showers and storms just about anywhere. Any convection will quickly dissipate after loss of heating with dry conditions overnight. Lows in the lower to mid 70s. && .SHORT TERM /MONDAY AND MONDAY NIGHT/... As of 330 AM Sunday... ...Dangerous Heat Persist... ...Record Breaking Temperatures... The Carolinas will remain under the influence of the upper ridge and Bermuda high pressure. Models continue to suggest that the heat will continue to build ever so slightly with record breaking high temps expected at 2 of our 3 climate sites(GSO and RDU-see climate section below) as most locations warm into the upper 90s, with some triple digits/lower 100s possible in the typically warmer locations. A Heat Advisory in all likelihood will be needed for the same area with heat indices again topping out in the 105 to 109 degrees. Some short term relief may come in the form of some widely scattered convection as the area remains vulnerable to weak disturbances moving through the area, with the seabreeze expected to be a little more active. Balmy overnight lows in the mid to upper 70s, which will also challenge record hi-min temps. && .LONG TERM /MONDAY THROUGH SATURDAY/... As of 257 PM Saturday... The main weather story for Monday and Tuesday will be the intense heat, given the pattern which features weak ridging and flow aloft, coupled with H8 temp anomalies of 4-6 deg C above normal. This will result in highs in the upper-90s both days, and some low-100s can`t be ruled out. Heat indices of 105+ are expected from the Triangle eastward on Monday, perhaps reaching as far west as the Triad by Tuesday. In terms of precip chances those days... coverage should be isolated at best both days given the overall weak forcing over the region. PoPs will increase on Wednesday as heights begin to fall in advance of a trough moving across the Great Lakes. With increasing flow above the BL, expect to see the Piedmont trough sharpen and improved low level convergence and subsequent outflow boundaries should be the primary lifting mechanisms for increased shower activity. Shower and thunderstorm activity, which may begin by early afternoon, may help keep high temps limited to the lower 90s. Rain chances will continue to increase, with well-above climo PoPs by Thursday and for Friday and possibly Saturday as well as the aforementioned trough pushes a cold front into the Mid Atlantic and Carolinas regions before stalling over us. That boundary, coupled with another plume of deep moisture will likely result in several rounds of heavy rains. However, that will also keep temps limited to near-climo values. && .AVIATION /06Z SUNDAY THROUGH WEDNESDAY/... As of 100 AM Sunday... Aside from some patchy fog at fog prone locations like KRWI, VFR will generally prevail overnight and into the afternoon. Isolated to widely scattered diurnally driven showers and storms are possible area-wide and have handled this low probability with tempo group between 19 to 22z at all TAF locations. Outlook: Isolated afternoon storms could result in sub-VFR conditions at TAF sites early this week, but otherwise VFR conditions are expected until the next front settles into the region with higher chances of convection and flight restrictions late Wed-Thu. && .CLIMATE... Record High Temperatures: July 14: KRDU: 101/1954 July 15: KGSO: 97/1974 KRDU: 99/1997 July 16: KGSO: 99/1915 KRDU: 101/1887 KFAY: 103/1937 July 17: KRDU: 100/1887 KFAY: 102/1932 Record High Minimum Temperatures: July 13: KGSO: 75/2017 KRDU: 78/2017 KFAY: 78/2017 July 14: KGSO: 77/1981 KRDU: 77/2017 KFAY: 80/2017 July 15: KGSO: 74/2019 KRDU: 76/1992 KFAY: 78/2015 July 16: KGSO: 75/2010 KRDU: 77/2010 KFAY: 78/1992 July 17: KGSO: 75/2013 KRDU: 80/1887 KFAY: 77/2019 July 18: KGSO: 76/1986 KRDU: 79/1887 KFAY: 77/2019 July 19: KGSO: 75/2016 KFAY: 77/2023 && .RAH WATCHES/WARNINGS/ADVISORIES... Heat Advisory from 11 AM this morning to 7 PM EDT this evening for NCZ008>011-025>028-040>043-075>078-084>086-088-089. && $$ SYNOPSIS...MWS NEAR TERM...CBL SHORT TERM...CBL LONG TERM...np AVIATION...CBL/BLS CLIMATE...RAH