Area Forecast Discussion
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195 FXUS62 KTAE 181944 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 344 PM EDT Thu Sep 18 2014 .Near Term [Through Tonight]...
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Now that the surface front has pushed through most of the area we are seeing dewpoints range from the upper 50s at Dothan and Albany to upper 60s at near the coast. PoPs are low tonight with the greatest chance (20-30%) over the Gulf, similar to what we saw last night. Winds will be light overnight and lows will be in the upper 60s. .Short Term [Friday Through Saturday Night]... A relatively low-amplitude wave currently near Arkansas should continue digging southeast, leading to the development of a broad mid-upper level trough centered just east of our area by Friday afternoon. Models indicate that this may close off into a low briefly on Saturday near the northeast Florida coastline. Either way, our forecast area is expected to be on the back side of the mid-upper level trough axis. Because of this, isentropic descent is noted at most layers (295-315K), associated with weak subsidence given our position relative to the trough axis. We will, however, remain in a low-level easterly flow regime near the base of a surface ridge axis. With PWATs close to September median values at TLH, this is a flow pattern that can lead to some isolated to scattered showers from the mid afternoon to evening. Given negating factors for large scale vertical motion, we opted to keep PoPs closer to the low end of guidance both Friday and Saturday (20-30%, with 40% far east). While model guidance does indicate some convective instability, these sort of patterns tend to favor low-topped convective showers versus thunderstorms, so the forecast wording reflects a lower chance of storms. The expanding low-level surface ridge and east to northeast flow should lead to some CAA in those layers. Model consensus 850mb temperatures are forecast to decrease about 3-4C from this evening through Saturday evening. The result should be a gradual cooling trend through the period, with highs on Friday from the upper 80s to around 90, and highs on Saturday in the mid 80s. It`s worth noting that Tallahassee has not observed a day with below normal temperatures (by avg temp) since August 1st, and that may finally occur during this forecast period (especially Saturday), although it will likely be very close. .Long Term [Sunday Through Thursday]... There is a little uncertainty in the models regarding the exact evolution of the mid-upper level flow pattern next week, although it has been a consistent trend to show significant amplification over North America. The one consistent trend has been the establishment of a persistent easterly low-level flow regime across our area as another strong surface high builds into the Northeastern US. This should keep isolated to scattered showers in the forecast (mainly in the late afternoon and early evening), with temperatures moderating close to seasonal normals.
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&& .Aviation...
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[Through 18Z Friday] VFR conditions and light winds should prevail through the period at all terminals. The only exception is a period of IFR at VLD from 9-14Z.
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&& .Marine...
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Much of the forecast period will be dominated by a surface high pressure ridge over the eastern US, which will place the coastal waters in an easterly flow regime on most days. Several periods of enhanced easterly flow seem likely: (1) from Friday to Saturday with SCEC winds possible offshore -AND- (2) beginning Wednesday with SCEC winds likely.
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&& .Fire Weather...
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RH values and other parameters are not expected to approach red flag levels during the next several days.
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&& .Hydrology...
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Generally light rainfall amounts are expected for the foreseeable future, except in very localized instances. Therefore, we are not expecting any significant flooding issues over the next week.
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&& .Preliminary Point Temps/PoPs...
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Tallahassee 69 90 68 86 67 / 10 40 30 30 20 Panama City 72 89 71 87 70 / 10 30 30 20 20 Dothan 66 89 68 85 65 / 0 20 20 10 10 Albany 68 88 68 85 65 / 10 30 20 20 10 Valdosta 69 87 66 84 66 / 10 40 30 40 20 Cross City 70 87 66 86 66 / 30 40 30 40 20 Apalachicola 71 87 72 84 71 / 10 30 30 30 20
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&& .TAE Watches/Warnings/Advisories... FL...None. GA...None. AL...None. GM...None. && $$ NEAR TERM...WESTON SHORT TERM...LAMERS LONG TERM...LAMERS AVIATION...WESTON MARINE...LAMERS FIRE WEATHER...DVD HYDROLOGY...LAMERS

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