textproduct: Jacksonville

KEY MESSAGES

For the latest NE FL and SE GA Daily Key Messages please visit: https:/www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf

- Isolated To Widely Scattered Afternoon Thunderstorms Today,

- Decreasing Chances Through the Week. Wednesday: Peak Heat Index 105-111 Most Areas. Major Heat Risk through the rest of the Week

- Moderate Rip Current Risk Beaches Today

NEAR TERM /THROUGH TONIGHT/

Main Highlights:

- Heat Advisory most areas today - Lower convective chances today

Stacked high pressure ridge axis will remain over south central FL area continuing the deep southwesterly flow. PWATs are about 1.8 to 1.9 inches, and so are still close to normal. Mean layer flow is a little weaker today and moisture levels in the 1000-700mb layer are drier than the past 2 days. This combined with warm temps aloft and the prevailing southwest flow will result in lower coverage/chances of showers and storms today, mainly in the 20-30 percent range. Strongest storm potential will be along the dominant west coast sea breeze and later in the afternoon along the east coast sea breeze. The latter feature will be able to move inland a little further than the past 2 days given the weaker flow. Any isolated convection this evening will tend to dissipate through 11 pm.

Less cloud cover, slightly warmer temps at 925 mb and 850 mb, and weak flow will enable even hotter temperatures than Mon and Tue. Currently have a heat advisory in effect today with some areas topping out close to 110. High temps in the mid to upper 90s anticipated and not far from record highs. These records are noted below in the climate section. Muggy overnight lows in the mid to upper 70s expected.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/

Main Highlights During This Period:

- Heat Advisory potential for Thursday and Friday Afternoons - Lower convective chances

Upper air ridging strengthens, limiting convection for the end of the work week. Precipitation chances Thursday remain isolated over north central Florida and the northeast FL coast south of St. Augustine in the afternoon and evening where some moisture lingers, with northeast Florida and southeast Georgia likely remaining dry on Friday. With mostly sunny skies and very limited showers and storms, dangerous heat will be the main concern both days. High temperatures will rise into the mid to upper 90s, even at the immediate Atlantic coast as southwesterly winds continue. Afternoon heat indices will approach 102-110 degrees both days, Heat Advisories may be necessary for portions of northeast Florida and the southeast Georgia coast.

LONG TERM /SATURDAY THROUGH TUESDAY/

Main Highlights During This Period:

- Heat Advisory potential Saturday Afternoon - Convective chances increase Sunday Onward

Convection will gradually increase daily Saturday onward, with coverage Saturday mainly isolated to scattered as both sea breezes push inland. Sunday, stronger southwest flow will bring higher convective chances closer to the I-95 corridor to the coast where the Gulf sea breeze meets the pinned Atlantic sea breeze later in the afternoon. Afternoon max heat index values remain dangerously high Saturday, approaching Heat Advisory conditions. By Sunday, temperatures drop a few degrees area-wide as more storms are expected.

Monday and Tuesday, precipitation chances increase to near 60-70% as a front approaches from the north. Higher cloud cover and storm chances will lower temperatures back to near normal in the lower to mid 90s to start off the new week.

AVIATION /12Z WEDNESDAY THROUGH 12Z THURSDAY/

VFR conditions will persist this morning. More limited convective coverage is expected today as upper ridging establishes over Florida. Still anticipate a 20-30 percent chance of showers and a storm, but low confidence on timing right now so have only included VCSH/VCTS. Otherwise, southwesterly flow will keep the sea breeze from pushing beyond KCRG/KSSI/KSGJ this afternoon. VFR conds expected again tonight following any isolated evening convection, except for the usual patchy MVFR fog at VQQ from 07-11Z.

MARINE

High pressure ridge will remain anchored across central and south Florida this week as low pressure troughing develops to the north. This pattern will maintain a southwest flow through early afternoon followed by late afternoon and evening wind surges from the south to Small Craft Exercise Caution wind speeds. The offshore flow will allow for a slight chance of afternoon and evening thunderstorm over the local coastal waters each day through the week. Mariners should expect locally strong wind gusts and frequent lightning with any developing thunderstorms.

Rip Currents:

Low to moderate risk of rip currents continues today through the end of the week due to fairly low surf conditions from prevailing offshore flow. Some enhanced potential still looks likely for the northern beaches by late afternoon from Mayport northward due to stronger southeast wind component each day. Surf remains generally in the 1-2 feet range.

FIRE WEATHER

PATCHY TO AREAS OF HIGH DISPERSION MAINLY NORTH OF I-10 FROM - Wednesday Through Sunday

High pressure will be the prevailing weather feature through Monday, with drier than normal conditions forecast through Saturday. This will lead to above average temperatures and dangerous maximum afternoon heat index values through Saturday. Southwesterly surface winds continue through Sunday, with patchy to areas of high afternoon dispersion north of I-10 expected each day. Despite drier air in place, minRH will remain above critical values. Precipitation chances increase early next week as a front approaches from the north.

Fog Potential and other remarks: Significant fog potential is not expected Tonight. Erratic wind gusts possible in and near thunderstorms, and at times, at a distance due to outflows.

CLIMATE

Summer heat is certainly here. There is potential for some locations to get to the century mark today with probability of this occurrence at about 20-30 percent. These probabilities look a bit higher for Thursday and Friday.

For the next few days, here are the record high temperatures that are within 3 degrees of the current forecast:

July 8th: KJAX: 100/1879 KAMG: 100/1986 KCRG: 100/2016

July 9th: KJAX: 101/1879 KGNV: 99/1932 KAMG: 100/1986 KCRG: 101/2016

July 10th: KJAX: 102/1879 KGNV: 99/1914 KAMG: 99/1980 KCRG: 99/2016

July 11th: KGNV: 100/1900 KAMG: 100/1980 KCRG: 99/1998

July 12th: KGNV: 99/1902 KCRG: 99/1981

PRELIMINARY POINT TEMPS/POPS

AMG 97 76 98 76 / 20 20 10 0 SSI 94 80 94 80 / 30 30 10 10 JAX 98 77 99 77 / 20 20 10 0 SGJ 96 77 97 77 / 20 20 20 0 GNV 97 75 98 75 / 20 10 10 0 OCF 96 75 97 75 / 20 20 20 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...Heat Advisory from 11 AM this morning to 7 PM EDT this evening for FLZ021-023-024-030-031-035-038-120-124-125-132- 136>138-140-220-225-232-233-236-237-240-322-325-333-340- 422-425-433-522-533-633. GA...Heat Advisory from 11 AM this morning to 7 PM EDT this evening for GAZ132>136-149-151>154-162-163-165-166-250-264-350- 364. MARINE...None.