textproduct: Raleigh

WHAT HAS CHANGED

As of 145 AM Tuesday...

* No significant changes to earlier forecast thoughts.

KEY MESSAGES

As of 145 AM Tuesday...

1) Unseasonably warm temperatures today through Wednesday may meet or exceed records.

2) Strong cold front brings showers Thursday, with a low-end threat for strong to severe storms in our southeast counties. After a brief cooldown Fri, temperatures rebound back above normal this weekend.

3) Another strong system approaching Sunday night and Monday may bring another low-end severe weather threat, mainly in our southeast. Well below normal temperatures are possible next week.

DISCUSSION

As of 145 AM Tuesday...

KEY MESSAGE 1... Unseasonably warm temperatures today through Wednesday may meet or exceed records.

Surface high pressure centered over Bermuda will strengthen and expand westward across the Carolinas and Southeast today, while ridging builds aloft, setting the stage for anomalously warm temperatures today through Wed, when low level thicknesses are projected to be 55-70 m above normal. Recent guidance, including the last several iterations of the deterministic NBM and statistical guidance from the GFS and ECMWF, all have widespread highs in the 80s both today and Wed, with Wed slightly hotter. Lows Tue night have also been consistently warm, in the upper 50s to mid 60s, close to the normal highs for this time of year. We're likely to come very close to or exceed daily high temp and warm low records at our three climate sites (GSO/RDU/FAY). This heat will be disrupted by the incoming cold front late Wed night through Thu.

KEY MESSAGE 2... Strong cold front brings showers Thursday, with a low-end threat for strong to severe storms in our southeast counties. After a brief cooldown Fri, temperatures rebound back above normal this weekend.

We continue to watch a strong cold front forecast to move through the region Thursday. Aloft, a pair of shortwaves are forecast to track east into the Carolinas and SE US during this time, with one across the OH Valley and another across the Deep South. Model and ensemble trends appear to be trending a tad slower, with the main period of shower activity coming early Thu into Thu afternoon, as opposed to Wed night. The front is expected to move through the majority of the region by Thu afternoon, after which cool high pressure settles in by week's end Fri. Rainfall amounts with the front range from a tenth to two tenths of an inch on the low end, to a quarter to one half inch or more on the median/high end. Given the ongoing drought conditions over the area, this rainfall will be beneficial. As for the severe threat, that remains conditional, with perhaps the best chance of any strong storms along our eastern counties. However, given that the system is coming through during the morning, instability appears somewhat lacking owing to cloudiness and modest lapse rates. The NCAR AI convective guidance shows a low-end severe risk, but the NSSL AI model shows a limited threat.

We cool off briefly behind the front to close out the work week with upper 50s to low 60s, but this is short lived as warmer air builds back in over the latter part of the weekend.

KEY MESSAGE 3... Another strong system approaching Sunday night and Monday may bring another low-end severe weather threat, mainly in our southeast. Well below normal temperatures are possible next week.

Our next significant chance of rain and possible hazardous weather will arrive Sun night into Mon with an approaching deep longwave trough and strong surface cold front, with model ensembles and AI guidance in good agreement on timing and amplitude. Showers and a few storms could occur ahead of and with the front, and if there is sufficient low level moisture recovery to boost prefrontal CAPE, a few storms could be strong, given the expected wind profile including a 40-60 kt low level jet and a corresponding long and broadly looping hodograph. But unfavorable frontal timing and expected prefrontal scattered showers Sun/Sun night may restrict any destabilization.

This strong cold front is expected to usher in much below normal temperatures by Tue and into mid week, with highs potentially only in the 40s.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

As of 600 AM Tuesday...

VFR conditions are expected to prevail across central NC through much of the 24 hour TAF period as weak high pressure and light southwesterly flow remain in place. There is a slim chance of a shower this afternoon, mainly in the west and south.

Outlook: Patchy morning fog/stratus is possible Wednesday. Otherwise VFR will dominate through Wednesday before conditions deteriorate late Wed night into Thursday with a strong cold front bringing showers and possibly a few thunderstorms, sub-VFR conditions, and gusty winds. VFR returns Fri into Sat.

CLIMATE

Record High Temperatures:

March 10: KGSO: 78/2016 KRDU: 81/1974 KFAY: 84/1974 March 11: KGSO: 86/1967 KRDU: 85/1925 KFAY: 87/1925

Record High Minimum Temperatures:

March 10: KGSO: 58/2016 KRDU: 57/2020 KFAY: 65/1964 March 11: KGSO: 62/2016 KRDU: 63/2016 KFAY: 63/2016

RAH WATCHES/WARNINGS/ADVISORIES

None.