Weather

984 
fxus64 kjan 111957 aaa 
afdjan 


Area forecast discussion 
National Weather Service Jackson MS 
257 PM CDT Sat Oct 11 2008 


Discussion...short term(tonight through monday) blocking pattern 
continues across the Continental U.S. With sharp upper trough in the west and large 
ridge in the east. Middle-upper anticyclone centered in the Ohio River valley 
will steadily build south-southwest into the Tennessee Valley Sunday/Monday. Meanwhile... 
moist low level Ely flow will persist across the Gulf states as 
moisture remains trapped under a stubborn inversion at 5-8k feet. 
Weak isentropic upglide at 300-305k also noted to increase slightly 
Sunday night with models in decent agreement that a few showers could 
form over about southeastern half of County warning forecast area. The cutoff middle level low near the 
Georgia coast drifts southwestward into the northestern Gulf helping to swing the moisture 
westward with an inverted trough as well. In any case...quantitative precipitation forecast should be 
very light and generally less than one quarter inch by midday Monday 
as precipitable waters  rise only from near 1 inch to 1.3 inches. 


Temperature guidance appears to be quite reasonable in the Ely flow 
regime with longer duration of cloud cover taken in consideration for 
eastern portions of County warning forecast area. Low temperatures should remain a little warmer 
in the lower to middle 60s the next couple of nights with highs on 
Sunday/Monday only reaching the upper 70s to lower 80s east half of the 
County warning forecast area while 80-85f rules the west half./40/ the bulk of the previous 
discussion covered conditions beyond Monday night and follows: 


Longer term(tuesday through friday)...the large upper trough over the 
western Continental U.S. Will ride over the large upper eastern Continental U.S. Ridge that 
will be retrograding southward to the Gulf of Mexico. This will result in 
warmer than normal temperatures through our period with slightly 
greater rain chances. Normals for this time of the year at most sites 
are in the lower 50s for lows and middle 70s for highs. By Tuesday the 
inverted trough will be west of our area...the large center of high 
pressure aloft will be over the Gulf states while surface high pressure 
ridges down the Appalachians across our area. The large upper trough 
will be over the northern plains with an associated cold front 
dropping into the Central Plains. Best rain chances Tuesday are 
expected in the northwest and southwest. Afternoon highs Tuesday 
will top out in the low to middle 80s. 


There are significant differences between the GFS and European model (ecmwf) with the 
timing of the cold front into our County warning forecast area but both models stall the 
front across our area enhancing rain chances for the end of the week. 
The GFS is more progressive with the upper ridge moving south of our 
area and brings the front in on Wednesday...the European model (ecmwf) being slower 
brings the front in on Thursday. By Friday even greater differences 
in the models occur with the European model (ecmwf) featuring a reamplification this 
time with ridging over the west and troughing in the east. The GFS 
trends to a broad upper ridge. The European model (ecmwf) would bring US a reinforcing 
cold front and rain Friday night versus drier weather with the GFS. 
Will lean toward a continuation of warm and mostly dry for now. The 
proximity of the cold front may hold temperatures over our Delta to 
near 80 degrees Wednesday but middle 80 highs area expected again for 
Thursday and Friday afternoons. Greater low level moisture over the 
County warning forecast area and no frontal passage should hold overnight lows in the 60s 
through the period. /22/ 


&& 


Aviation...VFR flight conditions are being observed at most taf 
sites this afternoon. However...MVFR ceilings are being observed 
across east and southeast Mississippi...kgtr...kmei...and khbg...as 
cloud cover and low level increases across these areas. Throughout 
the evening and overnight hours...look for clouds to continue to 
increase from east to west as an area of disturbed weather off the 
Georgia coast continues to slowly track west towards the region. Winds 
will remain easterly during this time at around 5 knots. Clouds will 
continue to increase from east to west Sunday morning with mainly 
broken to overcast ceilings expected between 2000-4000 feet...as 
easterly winds increase to between 5-10 knots. /19/ 




&& 


Preliminary point temps/pops... 
Jackson 64 79 65 84 / 0 1 11 16 
Meridian 62 78 63 83 / 0 4 20 22 
Vicksburg 63 82 63 84 / 0 1 8 12 
Hattiesburg 62 79 64 84 / 0 8 22 21 
Natchez 64 81 64 84 / 0 1 10 11 
Greenville 63 82 64 85 / 0 1 5 10 
Greenwood 63 82 64 85 / 0 1 9 13 


&& 


Jan watches/warnings/advisories... 
MS...none. 
La...none. 
Arkansas...none. 
&& 


$$