Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC
Issued by NWS Raleigh/Durham, NC
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410 FXUS62 KRAH 021803 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 203 PM EDT Sun Jun 2 2024 .SYNOPSIS... A trough will bring a chance of showers to the area through tonight. As we enter the week ahead, expect temperatures, humidity, and precip chances to increase through mid week. && .NEAR TERM /TONIGHT/... As of 203 PM Sunday... Slow moving mid level trough axis continues to move through the region this afternoon. Widely scattered showers/sprinkles continue primarily along and east of US-1 this afternoon, but are still struggling to amount to much as most ASOS/AWOS obs have only shown trace precip amounts. Meanwhile across western NC in closer proximity to the trough, areal coverage of showers is greater but precip amounts remain light, only a few hundredths of an inch. For the rest of the afternoon into the evening, fairly good model agreement in the idea of additional showers developing across the western Piedmont where forcing for ascent will me maximized near the trough. Rainfall amounts will be light and while there will be at least some instability in play (100-250 J/KG), strong/severe storms aren`t anticipated. Showers will dissipate as they move eastward but a stray sprinkle can`t be ruled out entirely across the Triangle this evening. The trough axis will swing through NC overnight. With continued ascent aloft and modest moist advection, additional showers are possible after midnight. Confidence in the finer details of this portion of the forecast remains low. Ingredients are in place for showers overnight, but figuring out the exact placement is a challenge. Meanwhile, CAMs are all over the place with their respective solutions (as would be expected within a weakly forced environment), so I drew in some broad 30-40 PoP values across most of the forecast area (primarily along and east of I-85). Rainfall amounts, where showers occur, should only amount to a few hundredths of an inch. With cloud cover in place tonight, look for mild lows in the low to mid 60s. && .SHORT TERM /MONDAY AND MONDAY NIGHT/... As of 155 PM Sunday... The trough axis from Sunday will roughly be over the area to start our Mon over the central Piedmont and along the US-1 corridor. This axis will slide SE toward the coast in the afternoon to early evening, with shortwave ridging building east from TN. The latest CAMs depict a possible leftover MCV from Sunday`s convection that may move across the Triangle, Sandhills, and Coastal Plain in the morning hours. While confidence is low on this feature, there will be very little CIN and some elevated CAPE of a few hundred joules to support spotty showers into mid-morning. As clouds start to erode by early afternoon and heating raises highs into the low to middle 80s, most guidance indicates instability of around 1000 J/kg and deep-layer shear of 10-20 kt with little to no CIN. Most high-res models suggest isolated to widely scattered storm activity could form just about anywhere in central NC with PW`s near the 90th percentile of 1.6 inches. Perhaps the more favored areas for isolated storms would be east of US-1 along lingering outflows/lift from the MCV and a sea-breeze, as well as over the northwest Piedmont where a lee trough should favor storm activity over the higher terrain and tracking ESE with the NW mid-level flow. We do not expect any storms to reach severe limits given the low-end shear. Most storm activity should wane after sunset with loss of daytime heating. Low temperatures should once again be near the middle 60s. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 317 AM Sunday... The extended forecast continues to show an unsettled pattern, with Saturday the only day with high confidence of dry conditions. Perhaps the most difficult aspect of the long term forecast is that the strongest features, a surface low and upper level low, should primarily remain over Canada. Weaker features, a surface cold front (which will bring some drier air but not much in the way of cooler air) and an upper trough rotating around the upper low while the low is over the Great Lakes, will be the forcing mechanisms for any precipitation, which will have lower predictability. Chance pops are expected on Tuesday primarily east of US-1, then all locations should have high chance pops on Wednesday and Thursday. Tonight`s model runs are showing the highest chances of rain remaining to the west of central North Carolina on Wednesday, then shifting the highest chances of rain north of the region on Thursday, a slightly different solution than what was shown 24 hours ago. There is fairly good agreement between deterministic and ensemble models that the cold front should move through late Thursday, then loiter along the coast Friday. This should keep chance pops east of I-95 Friday, with slight chance pops across the rest of the forecast area mainly due to the 00Z GEFS solution. With the front shifting offshore Saturday, that is the one day in the forecast with high confidence for dry conditions. Expect minimal variations in the highs and lows through the period - highs will range from the mid 80s to the low 90s while lows will be in the 60s. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... As of 110 PM Sunday... Mainly light sprinkles across the area at the moment but conditions remain VFR. Additional showers are expected later this afternoon, primarily around INT/GSO and there could be brief periods of MVFR ceilings within the strongest showers. Meanwhile to the east, conditions should remain dry (outside of the aforementioned sprinkle) through 00Z although some of the INT/GSO showers may make a run at RDU right around 00Z and I included a few hours of VCSH. Late tonight, most guidance indicates widely scattered showers across the area as a trough moves through NC. Elected to include a few hours of VCSH at RDU/FAY/RWI as this trough crosses the area although confidence in how this late night scenario will play out is low. Outlook: Additional, mainly diurnally driven showers and storms, are expected through much of this week as we return to a more typical June pattern. Highest storm chances are likely at INT/GSO although all 5 TAF sites could see impacts in the form of non-VFR cigs/vsbys within any showers that develop. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Leins NEAR TERM...Leins SHORT TERM...Kren LONG TERM...Green AVIATION...Leins