textproduct: Raleigh

WHAT HAS CHANGED

As of 300 AM Tuesday...

* Warmer today, 10-20 F above average and a category or two above the previous forecast and the most recent National Blend of Models

* A good chance to likely probability of rain across srn zones Wed morning, followed by possible Increased Fire Danger Wed afternoon (where rain does not occur prior)

* High confidence in at least a period of light to moderate rain between Saturday evening into Sunday.

KEY MESSAGES

As of 300 AM Tuesday...

1) Much warmer between a warm front that will retreat newd across the Carolinas and VA today and a pair of cold fronts that will move across cntl NC Wed and Wed evening

2) A good chance to likely probability of rain across srn zones Wed morning, followed by possible Increased Fire Danger Wed afternoon (where rain does not occur prior)

3) Widespread light to moderate rain is becoming increasingly likely late Sat night through Sun. Forecast details, such as amounts and areal coverage, remain uncertain.

DISCUSSION

As of 300 AM Tuesday...

KEY MESSAGE 1...Much warmer between a warm front that will retreat newd across the Carolinas and VA today and a pair of cold fronts that will move across cntl NC Wed and Wed evening

A warm front now over GA, one which separated on Mon 70sF from wrn GA wwd and across the Gulf Coast states from 40s-50sF across the Carolinas, will retreat newd across the Carolinas this morning and VA this afternoon. The portion of the warm sector that reached ATL, BNA, and BHM with observed high temperatures of 68, 71, and 75F on Mon, respectively, will overspread cntl and srn NC today. While unseasonably warm, daily records should be safe but approached within 5 degrees of the 1938 one of 74F at GSO.

KEY MESSAGE 2...A good chance to likely probability of rain across srn zones Wed morning, followed by possible Increased Fire Danger Wed afternoon (where rain does not occur prior)

A mid/upr-level cyclone over the srn Baja peninsula will eject ewd and across the srn Plains and lwr MS Valley through tonight and across the Southeast early Wed.

Meanwhile at the surface, a couple of closely-spaced cold fronts now stretching across IA/KS and MN/ND, respectively, will progress sewd and across the Middle Atlantic tonight and cntl NC Wed and Wed evening. A band of rain will probably accompany the deamplifying wave aloft and surface cold front across srn NC early Wed, where a tenth of an inch or so of rain will be possible. Post-frontal drying will be augmented by downslope flow, such that surface dewpoints will decrease through the 20s-30sF and be accompanied by still mild, compresionally-warmed 60sF temperatures Wed afternoon. Consequent afternoon RH around 25% will result. Nwly, post-frontal surface winds will also increase and become gusty into the 20s kts and support meteorological conditions supportive of Increased Fire Danger. Colder air will not arrive until the secondary cold front sweeps through the region Wed evening, with temperatures returning to near average, upr 20s to lwr 30s, by Thu morning.

KEY MESSAGE 3...Widespread light to moderate rain is becoming increasingly likely late Sat night through Sun. Forecast details, such as amounts and areal coverage, remain uncertain.

A strong mid/upper level short-wave will move across the southern Plains/Deep South Friday/Saturday before moving across the southeast Sunday into Monday. This system will feature a swly surge of anomalous PWAT ( up to ~1 to 1.25 inches; ~200 to 250 % of normal) into central NC by Sunday afternoon. At the sfc, a 1030 mb high off the New England coast will extend lingering nely flow across central NC Saturday/Sunday. Further west a sfc low will develop somewhere over the TN valley before advecting east and transferring energy to an offshore low through Monday via Miller B style.

This setup will likely lead to, at the very least, beneficial light to at times moderate rain over central NC during this period. There still remains some uncertainty wrt to the actual path of the sfc low (and the strength of upper forcing) and consequently dialing in QPF this far out is challenging. However, latest LREF ensemble probabilities for at least an inch of rain hover in the 50 to 60% range for much of our area. We'll see how things trend over the next few days.

While some locations south and east of Raleigh may get into the warm sector Sunday afternoon, most guidance keeps the best combination of shear and instability to our south. As such, think that any severe risk, if any, should remain to our south at this juncture.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

As of 100 PM Tuesday...

24 hour TAF period: Sunny-mostly sunny skies this aft will give way to overcast high clouds around/after midnight, with cigs lowering through the night. While VFR conditions are expected through 12Z Wed, LLWS is still expected as the LLJ strengthens ahead of a cold front. There is still some uncertainty wrt the timing, duration, and severity of the LLWS this eve-tonight, as it could start/end earlier than what is in the TAF, and could also be a bit more borderline in some locations. Winds should largely be swly at 5-10 kts ahead of the front, then veer around to nwly behind the front Wed morning. Additionally, rain chances increase from NW-SE ahead of the front as it moves across central NC Wed morn. Some sub-VFR cigs and visbys are possible with the rain/fropa Wed morning, most likely at KRWI and KFAY, and possibly briefly at KRDU. In the wake of the front, cloud cover will decrease from the NW through the end of the TAF period.

Outlook: Winds could be a bit breezy/gusty Wed aft/eve, mainly in the Triad. The next chance for precipitation and sub-VFR conditions will be Sat night/Sun, otherwise expect dry weather and VFR conditions to prevail.

RAH WATCHES/WARNINGS/ADVISORIES

None.