Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 280725 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 325 AM EDT THU JUL 28 2016 .Synopsis... An upper level disturbance will track just to the north of the region today and tonight around the hot high pressure over the Carolinas. A weak cold front is expected to move into central NC late Friday, stalling over the region for the weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 220 AM Thursday... ...Heat Advisory for all counties today (noon through 800 PM)... First things first, the dangerously high dew points in the 70s to lower 80s will combine with the higher temperatures today (96-101) to produce heat indices of 105-109 degrees, except 100-104 in the NW Piedmont. All zones will have a heat advisory from noon through 800 PM. It can not be stated enough for everyone to drink plenty of water, limit time outdoors, take breaks in the shade or in air conditioning, or relax by a fan to cool off. This is a dangerous heat wave - not necessarily because of the high temperatures (we are not breaking daily highs) - it is the dew points in the mid 70s to lower 80s setting records. Heat indices nearing 110 degrees will be felt in the southern and eastern part of the Advisory area. The chance of cooling convection today appears less than yesterday in all but the NW zones. A weakening mid/upper level short wave trough over the mid-Mississippi Valley, already aiding in strong to severe thunderstorms over northern TN, KY, southwest VA, and even the NW Mountains of NC early this morning, will lift NE over WVA/VA later today. At the surface, weak low pressure will develop over northwest NC and southwest VA this afternoon and track NE into northern VA this evening. ...A few severe storms are likely across northern NC this afternoon and early evening... While the bulk of the convection is expected to affect TN/KY/WVA/VA, some of the storms will affect/develop over the mountains of NC. Outflow boundaries may set off new convection, at least on a scattered basis, over much of NW and north-central NC mid afternoon into the mid-evening hours. This is where there will be a chance of isolated severe thunderstorms, with damaging wind the main threat. While the stronger mid-level flow is expected to be just north of the region, northern NC will be on the southern fringe of the increased mid=level flow, and it may actually be in the area where heating will be the strongest (given convection already ongoing to the northwest. MLCapes of 2500 J/KG are possible as dew points will be in the 70-72 range as temperatures reach 96-98. Given this instability, any storm that occurs will become capable of damaging wind. The threat will diminish rapidly this evening as is typically the case with strongly diurnally driven storms. We will carry 40-50 POP NW and N, with only 10 to 15 POP SE. Highs 96-101. Lows tonight 70-76. && .SHORT TERM /FRIDAY AND FRIDAY NIGHT/... As of 250 AM THURSDAY... The aforementioned short wave trough will be moving off the mid- Atlantic coast Friday, leaving subsidence and the potential for more of a westerly low level flow over NC Friday afternoon. Even through the temperatures will be just as hot as today, the dew points may mix out a bit more, especially in the western Piedmont. While a heat advisory will likely be needed again, it may be confined to areas east of the NW Piedmont (if the dew points are still expected to mix out into the mid to upper 60s there. Elsewhere, another hot humid day with heat indices likely at or very near 105. Highs may be just a bit lower than today, but 93-100 is still hot. POP will be much lower with mostly 10 percent or less any any given spot. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/...
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As of 325 AM Thursday... Ridging aloft extending from coast to coast in the mid-latitudes (30- 40 degrees N) will transition to a pattern of broad troughing aloft over the eastern US this weekend through early next week, followed by NW flow aloft by the middle of next week as an upper level ridge re-strengthens over the lower MS river valley and Deep South. With the above in mind, expect a cooling trend over the weekend with slightly above normal temperatures becoming near normal by early next week. With broad troughing aloft, expect above-normal chances for convection this weekend through early next week. With central NC situated on the southern periphery of the westerlies, an above normal potential for severe weather will exist if small amplitude waves and/or upstream convection /MCVs/ progress into/across the region, particularly in vicinity of peak heating. -Vincent
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&& .AVIATION /06Z THURSDAY THROUGH MONDAY/... As of 200 AM Thursday... There is a chance of strong to isolated severe storms this afternoon and early evening across the northern part of NC from KINT to KRWI, otherwise generally VFR conditions are expected with some patchy early morning ground fog. Outlook: Outside of isolated to scattered storms each afternoon/evening and some patchy early morning fog, expect predominately VFR conditions through Friday. && .RAH WATCHES/WARNINGS/ADVISORIES... Heat Advisory from NOON to 800 PM EDT TODAY for NCZ007>011-021>028- 038>043-073>078-083>086-088-089. && $$ SYNOPSIS...BADGETT NEAR TERM...BADGETT SHORT TERM...BADGETT LONG TERM...Vincent AVIATION...BADGETT

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