Area forecast discussion National Weather Service Detroit/Pontiac Michigan 601 am EDT Thursday Jun 20 2013 Aviation... //discussion... High pressure centered over Lake Huron will maintain control across the region through tonight. Mainly clear skies and light south to southeast winds during this time. //Dtw threshold threats... * none && Previous discussion...issued 328 am EDT Thursday Jun 20 2013 Short term...today and tonight 1022 mb surface high situated beneath slightly confluent middle level northwest flow will ease eastward with time through tonight... tending to anchor over Lake Huron. This will continue to provide plenty of clear sky and dry conditions. This process will yield a slight upward adjustment in the height field while veering the low level gradient gradually toward a south/southeast component by afternoon. Under full June insolation...this will translate into a 4-5 degree warming trend off readings noted on Wednesday. Highs look to arrive within the upper 70s/near 80 range. Lows tonight will also see a corresponding move upward within this moderating airmass. Readings largely in the 55 to 60 degree range. Weak middle level trough currently exiting the Dakotas will arrive during the early morning period. Slight increase in ascent along this feature may be enough to generate some high level cloud...but sufficient depth to the dry layer beneath will keep precipitation chances none. Long term...Friday through Wednesday Forecast reasoning for the next several days is unchanged. Despite a high confidence evolution to the large scale pattern, local weather will be strongly modulated by local & upstream convective trends which impairs predictability beyond day 2. Middle-level westerlies are forecast to emerge across the northern tier of the United States by the end of the week as impulses embedded within the large Pacific northwest low trigger multiple organized convective episodes across the northern plains/upper Midwest. This will allow a warm and humid airmass to spill eastward into the Great Lakes region yielding upper-end high temperature potential in the 90s for most of the long term. However, as is typical during the warm season, daily convective trends will play the first order role in determining actual observed temperatures. Therefore, moved forward in similar fashion to the inherited forecast which depicts slightly warmer than average temperatures hovering in the upper 80s. Support for such an approach is offered by numerous consecutive runs of the ECMWF, which has maintained that Southeast Michigan will remain favorably positioned along the edge of the middle-level cap for the next several days. This will put the County Warning Area in line to see both direct & indirect effects of multiple convective episodes and justifies a conservative methodology. Still see no reason to contend with European model (ecmwf) depiction of an MCS, or remnants thereof, impacting the area on Saturday. Although severe potential cannot yet be defined, probable early-day timing does suggest diminished severe potential. A growing Reservoir of instability will become established Sunday-Wednesday as a robust zonally-oriented eml ribbon is carried into the Great Lakes by emerging westerly flow. Per the usual, this will make convective potential increasingly dependent upon the ability of available forcing to overcome Stout middle-level capping. Marine... Favorable marine conditions will exist today and tonight as high pressure remains anchored over the region. A warmer and more unstable environment will gradually work into the region heading into next weekend. This will bring the next chance of showers and thunderstorms. && DTX watches/warnings/advisories... Michigan...none. Lake Huron...none. Lake St Clair...none. Michigan waters of Lake Erie...none. && $$ Aviation.....Mr short term...mr long term....jvc marine.......mr You can obtain your latest National Weather Service forecasts online at www.Weather.Gov/Detroit (all lower case).