textproduct: Raleigh

WHAT HAS CHANGED

* The threat for severe weather this evening has greatly diminished.

* Heavy rainfall threat appears probable Sunday into Monday.

KEY MESSAGES

As of 905 PM Saturday...

1) A Heat Advisory may be needed for portions of the area Sunday.

2) Marginal to Slight Risk of severe storms Sunday. A heavy rainfall threat is also possible Sunday.

3) Seasonably hot and humid summer pattern with unsettled weather continuing through midweek.

DISCUSSION

As of 905 PM Saturday...

KEY MESSAGE 1... A Heat Advisory may be needed for portions of the area Sunday.

After a hot day today with heat indices reaching 105-109F over much of eastern and southern portions of central NC, another Heat Advisory may likely be needed for a similar region of the Triangle, Sandhills and southern to central Coastal Plain Sun, with projected heat indices of 102 to 107 degrees prior to storm development.

KEY MESSAGE 2... Marginal to Slight Risk of severe storms Sunday. A heavy rainfall threat is also possible Sunday.

On Sunday, the frontal boundary looks to be starting out in the lower OH valley and VA, slowly sagging south into the region Sunday night to early Monday. A lee trough will still remain present. Both of these surface features should aid more coverage of storms, and CAMs suggest an earlier initiation in the early afternoon, peaking in the evening, but perhaps lingering into portions of the overnight hours as the boundary settles along/near the US-64 corridor. Similar to today, storms will be capable of damaging winds given slightly higher shear and similar thermodynamics. A heavy rainfall threat is also possible given high PW's around 2 inches and flow nearly parallel to the boundary.

KEY MESSAGE 3... Seasonably hot and humid summer pattern with unsettled weather continuing through midweek.

A stalled boundary associated with active weather Sunday into Sunday night will gradually washout and give way to southwesterly flow early next week, with central NC remaining on the warm and unstable side of the synoptic frontal zone. Relatively lower heights aloft associated with the broad cyclonic flow over the Great Lakes and Northeast, along with a weakness in the subtropical ridge over the northeast Gulf, should support continued periods of mainly afternoon/evening showers and storms Monday and Tuesday, before a stronger synoptic cold front attendant to a deeper upper trough is progged to push through the region. A better severe threat may unfold Wednesday with the front and what should be rather strong mid- level flow in the base of the trough, although the overall pattern of multi-day showers/storms and overturning lends some uncertainty to the threat.

Additional rainfall amounts of 1-2 inches seem reasonable Mon-Wed as PW remains anomalously high across the Southeast, due in part to the a weak surface trough or low that models have been indicating will develop over the northeast Gulf by Sunday. Higher rainfall amounts will depend on where showers and storms are more robust, with models generally favoring eastern NC.

AVIATION /23Z SATURDAY THROUGH THURSDAY/

As of 715 PM Saturday...

TAF period: The coverage of convection has dropped drastically between 21-23Z, and there is much uncertainty as to whether any organized convection will manage to develop once again. Considering there are still isolated thunderstorms, have maintained the TEMPO/PROB30 groups at RDU/RWI this evening, but have removed the PROB30 group from FAY as no thunderstorms have managed to develop that far south yet. VFR conditions should continue overnight, although the PROB30 mention was kept in FAY around sunrise for a potential drop in conditions. A west-southwest wind will develop late Sunday morning, and with greater coverage of thunderstorms expected tomorrow afternoon, have once again added PROB30 groups at all terminals except for FAY, where the better chance for thunderstorms will occur after 00Z.

Outlook: An approaching cold front Sunday that lingers into Monday should result in scattered to locally numerous showers and storms into early next week. Areas of stratus or fog will be possible each morning Mon-Wed. After a relative minimum in storms Tuesday, a strong cold front will risk additional storms Wednesday.

CLIMATE

Record High Temperatures:

July 19: KFAY: 101/2002

Record High Minimum Temperatures:

July 19: KGSO: 75/2016 KRDU: 80/1942 KFAY: 77/2023

July 20: KGSO: 75/2019 KRDU: 76/2025

July 21: KGSO: 76/2011 KRDU: 78/1932 KFAY: 80/2017

July 22: KGSO: 77/2011 KRDU: 78/2011 KFAY: 82/2017

RAH WATCHES/WARNINGS/ADVISORIES

None.