textproduct: Raleigh

WHAT HAS CHANGED

As of 225 PM Tuesday...

* None at this time.

KEY MESSAGES

As of 245 PM Tuesday...

1) Dry fuels combined with lower humidity and near record heat will promote fire weather concerns through the weekend.

2) An early-season heat wave will result in near record high temperatures from Wednesday through Saturday.

3) A late-weekend pattern transition is expected with a cold frontal passage. Low-end rain chances are expected on Sunday, followed by much cooler temperatures early next week.

DISCUSSION

As of 245 PM Tuesday...

KEY MESSAGE 1...Dry fuels combined with lower humidity and near record heat will promote fire weather concerns through the weekend.

The anomalous mid-level ridge will amplify along the eastern seaboard through the end of the week. Associated subsidence over the southeast will promote continued dry conditions at least through Saturday. Precipitation as a percentage of normal over the past 30 days is as low as 5 to 25% for portions of our area worsening the elevated drought conditions. As such, fuels have been anomalously dry for some time.

Winds will remain light Wednesday through Saturday, but with temperatures increasing into the lower to mid 90s, along with fairly deep mixing heights (and decreasing PWAT), RH should dip into the mid to upper 20 percent range each afternoon. A little bump in gustiness may be possible Thursday afternoon with the passage of a dry short-wave and again on Sunday ahead of and behind a cold front. Overall though, meteorological conditions (combined RH and wind) should largely remain sub-IFD criteria. However, given persistent dry fuels, near record temps, and poor overnight recovery for much of central NC, the NC Forest Service may request additional IFDs for portions of central NC to help with messaging their current state- wide burn ban.

KEY MESSAGE 2... An early-season heat wave will result in near record high temperatures from Wednesday through Saturday.

Anomalously strong subtropical ridging will persist over the Southeast US for much of the period from Wednesday through Saturday, other than a brief dry shortwave passage on Friday. At the surface, a Bermuda High will bring warm southwesterly flow to central NC during this time. 1000-850 mb thicknesses are modeled to be around the 95th percentile for this time of year, and forecast maximum and minimum temperatures get close to or reach record highs each day. Mostly lower-90s for highs and lower-to-mid-60s for lows are expected, which is around 15-20 degrees above normal. Can't rule out some mid-90s on Saturday, which looks to be the hottest day. For reference, this would get close to the hottest temperatures ever recorded any day in the month of April. See the climate section below for more details. Fortunately, humidity looks tolerable, with dew points mostly bottoming out in the lower-to-mid-50s each day, perhaps even some 40s especially in the west. So heat indices will be about 2-4 degrees cooler than the actual air temperatures each day. Still, several days of highs in the lower-90s could result in heat stress for sensitive individuals and those working and exercising outdoors.

KEY MESSAGE 3... A late-weekend pattern transition is expected with a cold frontal passage. Low-end rain chances are expected on Sunday, followed by much cooler temperatures early next week.

A broad mid/upper trough will advance into the Eastern US from the Plains this weekend. An associated cold front will move across central NC on Sunday. This may result in showers and isolated storms, but at this time both the GFS and ECMWF and most of their ensembles move it through too early in the day for much instability to develop (a few hundred J/kg of CAPE at most). This combined with the best forcing and moisture from the trough focused to our north mean rainfall amounts look light, with ensemble means only a tenth of an inch or less. So there will be very little if any relief from the drought. It will turn significantly cooler on Monday and Tuesday with below-normal temperatures (highs mainly in the upper-60s to lower-70s, lows in the 40s).

AVIATION /18Z TUESDAY THROUGH SUNDAY

As of 104 PM Tuesday...

VFR conditions will persist through the 24 hr TAF period. Sswly sfc flow will remain light this afternoon, with a few gusts of up to 20 kts possible at KFAY/KRWI this afternoon. Similar light sswly sfc flow is expected Wednesday.

Outlook: Sub-tropical high pressure will favor warm, dry, and VFR conditions in cntl NC through Sat. A cold front will bring a low-end chance of showers to central NC on Sunday.

CLIMATE

All-Time Records for April

KGSO: 95 on 4/28/1915 KRDU: 95 on 4/23/1980 and 4/28/1896 KFAY: 96 on 4/12/1930

Record High Temperatures:

April 14: KGSO: 90/1922 KRDU: 91/1941 KFAY: 93/1922

April 15: KGSO: 90/2006 KRDU: 92/1941 KFAY: 95/2006

April 16: KGSO: 88/2002 KRDU: 92/1941 KFAY: 94/2006

April 17: KGSO: 90/1967 KRDU: 93/1896 KFAY: 92/1941

April 18: KGSO: 90/1976 KRDU: 95/1896 KFAY: 93/1941

April 19: KFAY: 94/1941

Record High Minimum Temperatures:

April 15: KGSO: 65/2006 KRDU: 64/1993

April 16: KGSO: 66/2006 KRDU: 64/1912 KFAY: 69/1934

April 17: KGSO: 63/2002 KRDU: 67/1896 KFAY: 66/1921

April 18: KGSO: 66/1909 KRDU: 63/1941 KFAY: 67/2002

April 19: KRDU: 67/1896 KFAY: 67/2002

RAH WATCHES/WARNINGS/ADVISORIES

None.