574 FXUS62 KCHS 282038 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 338 PM EST Mon Jan 28 2019 .SYNOPSIS... A strong cold front will approach the forecast area late tonight and move through on Tuesday. The front will push offshore Tuesday evening and be followed by high pressure into late week. A more unsettled pattern may develop by next weekend and into early next week with moderating temperatures. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Tonight: Southwesterly flow will prevail aloft as shortwave energy digs across the Deep South on the southern periphery of a cold upper low over the Northern Plains and Upper Midwest. The column will stay quite dry per model soundings and time heights, though there will be an increase in upper level moisture after midnight. The forecast is dry as a result. Skies will start off the tonight period clear, but cirrus will spread in steadily through the latter half of the period. Lows tonight could be tricky depending on how cloud cover evolves and the onset of light southerly flow ahead of an approaching front. We could hit our lows early in the period, and then see temperatures either hold steady or rise through sunrise. The forecast features low 40s in most areas, with mid 40s along the immediate coast. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... Tuesday: High pressure will quickly give way to an approaching cold font. The front is on target to push offshore during the early evening hours. Although moisture transport vectors suggest low-level moisture return ahead of the front will be poor, the front appears to bring its on source of moisture with it and will be sufficient to support a band of numerous to widespread showers. The latest guidance does suggest the band of showers will begin to quickly dissipate as it approaches the coast, so there is some uncertainty on exactly how far east the band will survive. Time heights suggest the forcing for assent will be decreasing with time as the supporting southern stream shortwave becomes positively tilted. Pops will range from 60% along the coast to 80% across the interior. The risk for tstms is minimal. Rain chances will decrease from west-east late afternoon/early evening with dry conditions expected to prevail through the overnight periods. Highs will peak in the lower 60s for most areas. Overnight lows will range from the mid 20s well inland to the lower 30s at the beaches. Wind chill values at daybreak Wednesday will range from the upper teens inland to the lower 20s at the coast. Wednesday through Thursday: Arctic high pressure will quickly moderate through the period as high pressure slowly moves offshore into the western Atlantic. Highs from the upper 40s/near 50 Wednesday will warm into lower-mid 50s for many areas for Thursday. Lows Thursday morning will range from the mid 20s well inland to the lower 30s at the beaches. Wind chill values at daybreak Thursday will drop into the lower-mid 20s. Lake Winds: A highly marginal Lake Wind Advisory may be needed Tuesday Night in the wake of a cold front. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... A gradual warming trend will likely develop as the surface high to the north slowly moves east-northeast while a low amplitude mid to upper level ridge tries to build from the west. After a cold start Friday morning, temperatures are expected to warm to above normal Friday through Monday. Surprisingly, global models are in decent agreement with the large scale pattern, even as far out as Sunday and Monday, showing a short wave trough moving well north of the region by Sunday and Monday. As this shortwave moves well north, a band of moisture, possibly associated with a surface warm front, moves across the area. Therefore, have gone with low end chance PoPs later Sunday and Monday. Otherwise, no significant rainfall chances are expected over the rest of the period. && .AVIATION /21Z MONDAY THROUGH SATURDAY/... VFR conditions are expected to prevail through 18z Tuesday. A cold front will approach the terminals Tuesday afternoon. Expect gusty southwesterly winds ahead of the front. Any showers along the front are currently expected to be after 18z. Extended Aviation Outlook: Risk for flight restrictions Tuesday afternoon. No concerns thereafter. && .MARINE... Tonight: Weak high pressure will get increasingly displaced to the east as a strong cold front approaches from the northwest. The period will start with light flow in the evening. Then by late tonight southwesterly winds will increase into the 10-15 knot range. Seas are expected to remain in the 2-4 foot range, and up to 5 feet in the outer reaches of the outer Georgia waters. Tuesday through Saturday: A strong cold front is expected to move through the waters Tuesday evening. Still expect winds to increase to low-end Small Craft Advisory levels behind the front Tuesday night. Cold high pressure will hang on north of the waters through Thursday, then begin to shift northeast Friday and Saturday. No highlights are expected Wednesday through Saturday. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...BSH SHORT TERM...ST LONG TERM...RFM AVIATION...BSH/ST MARINE...BSH/ST