185 FXUS63 KDTX 141618 AFDDTX Area Forecast Discussion National Weather Service Detroit/Pontiac MI 1118 AM EST Thu Feb 14 2019 .UPDATE... Minor updates to the forecast this morning to add flurries along and north of existing pattern of radar echoes lifting toward the I-94 corridor. These higher based flurries are associated with a transient corridor of isentropic ascent that will lift through Southeast Michigan through mid-afternoon. Also increased temperatures by a substantial margin in the far south where readings are already in the mid 30s at 16Z. Were it not for the snowpack, confidence in highs in the 40s areawide and approaching 50 in Detroit would be considerably higher. As it is, will hold current temps topping out at 40 along/north of the glacial ridge but increase highs to the upper 40s south where snow depth is analyzed at 2 inches or less. Remainder of forecast remains on track with all rain tonight and isolated showers possible anytime after 21z as stronger warm advection noses into the area. Warm temps will hold steady until the cold front arrives after 08z. && .PREV DISCUSSION... Issued at 514 AM EST Thu Feb 14 2019 AVIATION... Dry and stable low level conditions will ensure plenty of clear sky across the lowest 8-10k ft throughout the day light period. Modest increase in south to southeast winds will occur as the gradient strengthens immediately downstream of low pressure set to lift into the northern great lakes tonight. Increase in moisture tied to that attendant cold frontal passage will bring lowering cigs and window for light rain tonight. A few wet snowflakes may mix in at MBS, but of little consequence. Strong post-frontal westerly winds will emerge Friday morning. Gusts to 25 knots throughout the morning period. DTW THRESHOLD PROBABILITIES... * Medium for cigs below 5000 ft tonight. PREV DISCUSSION... Issued at 225 AM EST Thu Feb 14 2019 DISCUSSION... NEAR TERM / TODAY THROUGH TONIGHT As of 225 AM EST...A much quieter night compared to recent nights continues across the region with surface ridging in place. A brief period of clearing earlier this evening allowed temperatures to quickly dip into the upper teens to lower 20s, but mid and high clouds streaming in from the upper Midwest will allow temperatures to hold steady and even rise a few degrees towards daybreak as low- level warm air advection begins to ramp up ahead of the next system. Northern stream energy diving southeast from Manitoba will spurn cyclogenesis over the upper Midwest today, with the surface low tracking northeast well north of the region into the northern Great Lakes by tonight. Strengthening low-level southwesterly flow will help drive a warm front north across the region as the day progresses, placing southeast Michigan well within the warm sector as 850 hPa temps peak around 2 C this afternoon. High temperatures will easily rise through the 30s, and likely peak around 40 for most areas south of M-46. The low pressure system will deepen rather quickly into tonight, from around 1001 hPa over northeastern Iowa to around 990 hPa as it tracks across the Straits. The bulk of the dynamics and deeper column moisture associated with this system will be displaced to the north, resulting in a forecast featuring a chance for showers late this afternoon into this evening transitioning to a few wet snowflakes early tonight across areas north of M-46. Precipitation should largely end after midnight, with less than an inch of potential snow accumulation where the boundary layer can cool enough for wet snow to mix in with the rain showers. The systems cold front will push through shortly after midnight as well, with ensuing cold air advection in its wake allowing low temperatures to settle in the 20s. As the low deepens, the pressure gradient will tighten across the region resulting in gusty winds developing tonight, aided by efficient mixing in cold advective flow. Gusts tonight of 25-35 mph will be possible, with a few sporadic gusts to 40 mph north of the I- 69 corridor not out of the question. SHORT TERM / FRIDAY THROUGH SATURDAY NIGHT Developing split flow pattern aloft, with stable confluent flow over the central Great Lakes, will result in a quiet short term period featuring dry weather and high pressure. Cloud cover will likely linger through Friday with the low-level thermal trough overhead (850 hPa temps -9 to -12 C), but surface high pressure becoming more established by Saturday should allow for clearing skies. Despite the thermal trough overhead Friday, high temperatures will still rebound to the upper 20s to lower 30s. Winds will continue to be gusty throughout the day Friday with the lingering pressure gradient, with gusts 20-30 mph common. Winds will slacken Saturday with the building high, but with a light northerly flow developing, highs will struggle to reach into the upper 20s. Lows Friday and Saturday night in the teens. LONG TERM / SUNDAY THROUGH WEDNESDAY Shearing southern stream energy will move across the northern Ohio Valley early Sunday, with the potential for light snow with minimal accumulations at best. High pressure then looks to become established over the region for early next week with dry weather, before the next southern stream wave possibly clips portions of the region midweek. Still a lot of uncertainty in this solution with broad split flow from Hudson Bay to the Ohio Valley. Temperatures will start out the long term period slightly below normal, but moderate slightly to seasonal averages by midweek. Monday night looks to be the coldest night of the upcoming week, with the potential for northern areas to see lows dip into the single digits. MARINE... Modest wind speeds from a southerly direction today as a ridge of high pressure exits to the east. A strengthening low pressure system will then track into the region tonight. This system will bring a period of strong westerly winds as it exits the region on Friday. Increasing likelihood for gusts to reach gales over northern and central sections of lake Huron, prompting the issuance of a gale watch for this time. These conditions will gradually ease Friday night as winds turn northwesterly. More favorable marine conditions arrive this weekend as broad surface high pressure builds into the region. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...Gale Warning from 5 AM to 4 PM EST Friday for LHZ363-421-422- 441>443-462>464. Gale Warning from 5 AM to 10 PM EST Friday for LHZ361-362. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ UPDATE.......JVC AVIATION.....MR DISCUSSION...IRL MARINE.......MR You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.