Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 010133 AFDRAH Area Forecast Discussion National Weather Service Raleigh NC 833 PM EST Tue Feb 28 2017 .SYNOPSIS... A warm and blustery southwest flow will continue across the region through Wednesday. A strong cold front will cross the area Wednesday night, followed by clearing skies and cooler temperatures for the latter half of the week. && .NEAR TERM /THROUGH TONIGHT/... As of 830 PM Tuesday... Light rain has entered the NW Piedmont as evidenced by radar and surface observations. Although beginning to deteriorate, some modest returns to the southwest of the current rainfall should be able to hold together long enough to make it through much of the western Piedmont but uncertain whether or not these will be able to hold together long enough to reach US 1 or points east. What may be helpful is that moisture will begin to fill in the low levels to the east and thus help whatever precipitation is left get to the surface more easily. At the very least a low stratus deck should begin to form across the entire eastern half of the CWA if not more. Winds should stay up enough to avoid any problems with fog but low stratus will certainly remain prevalent through the morning. Lows in the low to mid 60s with highest temps across the southeastern counties. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... As of 320 PM Tuesday... A s/w dropping sewd out of the upper Midwest into the Great Lakes will propel a lead s/w across the TN Valley Wednesday and into the Carolinas Wednesday evening. This system will be accompanied by a band of convection. A strengthening low level jet (50-60kts) will support a strongly kinematic atmosphere. While the low level air mass will be toasty with afternoon temps in the upper 70s-lower 80s. Sfc dewpoints are forecast to be no worse than around 60-lower 60s. This is supportive of a weakly unstable air mass but not supportive of a widespread severe weather event. So, expect a band of convection with locally strong/severe wind gusts to enter the western Piedmont sometime close to or after sunset, then progress east into the highway 1 corridor in the 9 PM-Midnight time frame. Expect intensity of the showers/storms to diminish as it enters a relatively more stable air mass. Ahead of the showers and storms, southwest sfc winds will be gusty/windy with sustained winds 15-20 mph and gusts 30-35 mph. A deck of mid-high level clouds may deter insolation enough to prevent optimal mixing, leading to slightly lower wind gusts. Conversely, if more sunshine occurs than expected, wind gusts around 40 mph may occur, prompting the need for a wind advisory. Band of convection expected to progress east and exit our coastal plain counties in the overnight hours. Low level flow from the nw will advect a drier more stable air mass, leading to a decrease cloud trend nw-se overnight. This clearing line will likely lie across the Triangle region at daybreak, then progress swiftly se early Thu morning. Low level cold air advection will send temperatures tumbling north and west of Raleigh, leading to min temps in the low-mid 40s. Later arrival of the colder air will result in min temps in the 50s se of Raleigh. && .LONG TERM /THURSDAY THROUGH TUESDAY/... As of 220 PM Tuesday... Thursday and Thursday Night: The current timing of the cold front may result in a slight chance of showers lingering over the far southeast early Thursday morning, but the rest of Central NC should be dry and beginning to clear. Skies will continue to clear through the day, however the cold air advecting into the region behind the front will likely limit highs to upper 50s NW to mid 60s south. Winds will be northwesterly behind the front and remain quite strong through the day Thursday afternoon with sustained winds up to 15 kts with gusts to around 20 kts, diminishing late in the afternoon. Expect winds of 5 kts or less overnight, backing slightly to more westerly. The light winds combined with clear skies and continued cold advection will yield lows generally in the mid 30s across the area Thursday night. Friday through Sunday Night: This period is expected to remain dry. Highs Friday will be in the mid 50s NW to mid 60s South, though they will be somewhat dependent upon the timing of a reinforcing dry cold front expected to push through late Friday/Friday night. Highly confident the coldest temperatures will occur Saturday morning as a result of the aforementioned cold air (mid to upper 20s), as well as the surface high moving overhead. With the high overhead and continued northerly flow, highs Saturday will struggle to recover, maxing out in the low to mid 50s. Expect moderating temperatures once again through Sunday night as southerly flow sets up once again. Lows Saturday night in the low to mid 30s, increasing into the mid 40s by Sunday night and highs Sunday in the mid 60s. Monday and Tuesday: The surface high will shift off to the southeast as yet another low pressure system develops out west. The warm southerly flow increases over the Carolinas Monday and Tuesday as the aforementioned system moves east toward the Mid-Atlantic. There are still issues with timing of this system, thus confidence is somewhat low in that regard, but expect a chance for showers ahead of the front as it moves into the region early to mid week. As expected, temps will increase ahead of the front and decrease in its wake, however the timing is uncertain at this time. && .AVIATION /00Z Wednesday through Sunday/... As of 705 PM Tuesday... A band of showers will cross central NC this evening, bringing a brief period of MVFR vsbys, although cigs should remain predominantly VFR. Then, clouds will thicken and lower within a strengthening low level flow from the SW, and a period of MVFR cigs is likely at all sites later tonight (most likely 09z-13z), with some spots potentially seeing a short period of IFR cigs. Cigs should then lift to VFR gradually between 13z and 15z, remaining VFR through the end of the TAF valid period. Surface winds, currently from the S or SSW under 10 kts, will strengthen from the SW overnight, increasing to around 15 kts toward daybreak, then to sustained 15-25 kts with frequent gusts to 25-35 kts starting mid morning. These deeply strong winds may induce mechanical turbulence which could bring about difficulty handling some smaller aircraft. Looking beyond 00z Thu (early Wed evening), a line of showers and strong thunderstorms is expected to cross central NC Wed evening, bringing a high chance of sub-VFR conditions and a threat of damaging wind gusts (on top of the already-strong and -gusty winds). This convection will be ahead of a cold front that will sweep through the area Wed night, mainly after midnight. Skies will clear out for Thu with VFR conditions and NW winds. VFR conditions will hold Thu through Sun as high pressure builds over the area. -GIH && .FIRE WEATHER... As of 445 PM Tuesday... A cold front will cross central NC Wednesday night. Out ahead of the boundary, south-southwest 15-20 mph expected with gusts 30-40 mph. Minimum RH values Wednesday afternoon should bottom out 45-50 percent. Scattered convection should occur Wednesday night, though precip will be in the form of showers, and fall in less than an hour. This will not allow the rain to soak into the dry/dead grasses/leaves. Minimum RH values Thursday afternoon will fall to near the critical level of 25 percent. Gusty NW winds are expected Thursday morning though the winds are expected subside Thursday afternoon (at the time when the RH reaches the critical level). A secondary cold front is expected to cross central NC Friday afternoon. Again, RH values will bottom out around 25 percent. Sfc winds may gusts 20-25 mph out of the NW by Friday afternoon. These parameters may result in increased fire danger over the region. This may require the issuance of fire weather statements, per coordination with the NC Forestry Service. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...WSS/GIH NEAR TERM...ELLIS SHORT TERM...WSS LONG TERM...KC AVIATION...Hartfield FIRE WEATHER...WSS is the U.S. government's official web portal to all federal, state and local government web resources and services.