Marine Weather and Tide Forecast for Cynthiana, OH

NEAR TERM /UNTIL 6 PM THIS EVENING/
Surface high pressure remains the primary weather influence today, keeping conditions dry. This system will begin to shift eastward throughout the day as it drifts towards the Atlantic coast. Return flow on the backside of the surface high will result in an influx of seasonably warm air, along with a gradual increase in humidity values. With the WAA and plenty of insolation, highs will climb back into the middle 70s to near 80 in our far south.

SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/
Skies will remain clear for the majority of the night before clouds build in from the west ahead of the next system. However, a tightening pressure gradient will lead to a response in surface winds, increasing southerly flow overnight. This will result in mild overnight lows in the 60s across our CWA

The main focus remains on the severe potential for Tuesday. CAMs now offer a little more insight on timing and storm mode. Models continue to highlight moderate instability developing during the day, but there does seem to be a trend towards an earlier onset of storms. SBCAPE values of 1500-2000+ J/kg still seem probable, with the highest values expected near the Tristate. Wind shear profiles still appear to be marginal, but sufficient enough to lead to organized convection (especially with the forcing of a cold front).

By late morning, isolated cells may begin to develop across eastern IN/far western OH with a pre-frontal trough. Large hail would likely be the primary threat with any of these discrete cells earlier in the day, but given that some supercells could develop, an isolated tornado cannot be ruled out (but tornadoes do not appear to be a primary threat). As we progress into the early to mid afternoon, additional storm development occurs with the moderate levels of instability and increased forcing ahead of a cold front. This will likely result in more clustering of storms, perhaps forming a QLCS during the afternoon. Complex of storms would continue to move eastward with the progression of the cold front, with damaging straight-line winds now becoming the primary threat (although large hail and a spin-up tornado are still at play). It appears that the severe threat would likely diminish by the early to mid evening hours given the latest hi-res model trends showing a fast progression of these storms.

LONG TERM /TUESDAY NIGHT THROUGH MONDAY/
While initial line of convection may already have cleared the area before the start of the period, the cold front will still be moving through the region on Tuesday night. This combined with a trailing short wave moving up the Ohio Valley will result in more showers and thunderstorms, mainly in the evening. It is unclear whether the atmosphere can recover sufficiently in the wake of the initial line for this additional activity to pose any threat. More than likely, instability will have waned enough to limit the strength of any storms, but will have to keep an eye on how this evolves.

The front will get through the entire forecast area before stalling across Kentucky. It will start to move back north on Wednesday afternoon, likely getting back into southern counties and then lifting across the entire area on Wednesday night. This will result in continuing chances of showers and thunderstorms.

A more robust, but weakening, short wave will lift out of the mid South on Thursday and track across the region Thursday night. This will be just in advance of a digging short wave from the northern stream that will swing through Friday night. Showers and thunderstorms will increase in coverage as we head through Thursday with a cold front pushing through Thursday night. At least scattered showers will continue on Friday with a secondary trough moving through.

Ridging at the surface and aloft will build in for the weekend.

Temperatures will remain above normal until the cold front passes.
There will be a brief cool down, for a day or two, with readings rebounding back above normal for Sunday.

AVIATION /18Z MONDAY THROUGH SATURDAY/
Through this evening, southerly flow in the low levels will begin to increase across the region as a mid level ridge axis builds northward into the central Great Lakes and middle Ohio Valley. VFR conditions will prevail with southeast to south winds varying from about 8 to 12 knots.

For overnight, the mid level ridge axis will shift off to the east.
Some mid and high level clouds will begin to increase from the west ahead of the next weather system. At the same time, a low level jet will increase and move into the region. Southerly winds at the surface will increase overnight with some gusts in the 20 to 25 knot range possible along and north of the Ohio River by 12Z. The low level jet will also bring a period of LLWS. Moist flow will be increasing as well, and in the WAA, a chance of showers and thunderstorms may encroach western terminals by 12Z.

On Tuesday, low pressure will move northeast from the western Great Lakes into southeast Canada. Its attendant cold front is forecast to move southeast into our region. At this time, it appears that an embedded mid level disturbance will combine with a prefrontal trough axis to become the impetus/focus for shower and thunderstorm development. This activity should increase in coverage across western areas between 16Z and 18Z, and then it should propagate east/southeast through the afternoon. PROB30s have been used with predominate thunderstorms beginning in the west around 18Z. It will be breezy with south to southwest winds 12 to 18 knots with gusts between 25 and 30 knots. Synoptic winds should decrease toward evening as the low moves farther away and the pressure gradient decreases as well as decoupling of winds aloft.

OUTLOOK...Thunderstorms decreasing in probability Tuesday night.
Some MVFR ceilings may develop Tuesday night into the first part of Wednesday. Thunderstorms possible Wednesday into Wednesday night.
MVFR/IFR conditions likely Thursday into Thursday night along with a chance of thunderstorms. MVFR conditions possible Friday.

ILN WATCHES/WARNINGS/ADVISORIES
OH...None.
KY...None.
IN...None.