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Area forecast discussion 
National Weather Service northern Indiana
704 am EST Friday Nov 27 2015

issued at 658 am EST Friday Nov 27 2015

Rain will overspread the entire area today. Highs in the 50s will
be reached early in the day...then temperatures will fall through
the 40s into the afternoon. Lows Saturday morning will be in the
upper 20s to lower 30s.


Short term...(today and tonight)
issued at 348 am EST Friday Nov 27 2015

Eastward Peel of northern stream wave into northern upper Great
Lakes today to afford emergent split flow pattern surrounding
rexed cutoff cyclonic obstruction over intermountain region
through the short term period. Shortwave approach providing impetus to
finally force eastward shunt of deep moisture plume along with
collocated warm air conveyor/i295k isentropic ascent with 8-8.5
g/kg mixing ratio plume. Solid anafrontal precipitation shield
along with heightened forced ascent per frontal wave/featuring
succinct 3mb/3 hour couplet/ near kstl to track eastward along i70
corridor today. 20-30m/12 hour 500 mb height falls along with County Warning Area
favorably situated within divergent ulvl pattern within right
entrance of eastern Canada/upper Great Lakes jet axis. Upped quantitative precipitation forecast/probability of precipitation far
western/northwestern County Warning Area in near term...with assured categorical/100 probability of precipitation
progressing southeastward through County Warning Area today. Added late am mention of areas
of fog...primarily in northwestern third of County Warning Area in vicinity of hir am rafl/frontal
col. Held line on temperatures to no higher than warmest 3 hourly temperatures
in dynamic/non diuranal thermal evolution. With time frontal zone
pivots increasingly southerly advance...lying out through Northern
Ohio valley late tonight. Slightly slower exit/retention of hir
probability of precipitation through southeastern/southern County Warning Area as progression of trailing edge of
deeper moisture slows. Though as impact of system relative ascent
lessens with time late afternoon/overnight...quantitative precipitation forecast amounts should
trail off considerably. Did not introduce rasn mix along northern
edge of precipitation flow farther north more neutral in
isentropic framework...still relatively deep maximum tw layer aloft
and questionable ice introduction for realized seeder/feeder


Long term...(saturday through thursday)
issued at 348 am EST Friday Nov 27 2015

Main question for Saturday will be how much...if any...precipitation
remains in our County Warning Area after 12z. Low level front expected to stall
over the Ohio Valley as it becomes aligned parallel to the mean
flow aloft and increasingly orphaned from parent forcing. Still a
lot of uncertainty with regard to how far south Theta-E trough
pushes and how fast. Latest NAM and GFS suggest a primarily dry
Saturday but European model (ecmwf) as well as latest WRF-arw and nmm show a much
different picture with rain as far north as the toll Road through
Saturday evening. Did increase probability of precipitation a bit for Saturday but
maintained a tempered approach given majority of guidance in favor
of a more substantial southward push of frontal boundary.

Sunday will be dry but pinwheeling western Continental U.S. Upper low will
send front back north on Monday with a healthy slug of 295k
isentropic ascent and moisture advection. Some precipitation virtually
assured just a question of when and how much. Pushed up timing a
bit based on bulk of latest models indicating precipitation over our County Warning Area
no later than Monday afternoon. Forcing not particularly
impressive but precipitable water values do climb back above 1 inch and most
locations will probably squeeze out a tenth or two. Chance of rain
then continues through early Tuesday morning as cold front crosses
the area. Some lake enhanced rain or snow is possible Tuesday
night into Wednesday as midlevel circulation passes over the Great
Lakes. Amounts will be limited though and primarily confined to
our northern counties.


Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 646 am EST Friday Nov 27 2015

Continue to anticipate sharp deterioration of conds this am with
IFR conds developing soon at ksbn as surface frontal boundary passes next
hour. Period of LIFR still possible as mentioned in 06 UTC
discussion...16-19 UTC with visibilities below 1sm and/or ceilings/vertical velocity below 500
feet at ksbn though present indications are that probability of
occurrence too low for tempo group. At kfwa continued low level wind shear mention
through 14 UTC with latest second gate kiwx vwp at 55 kts. Even
after rain shield diminishes/shunts southeastward of kfwa later
tonight...still expect Richer moisture field to IFR to linger
longest at kfwa with improvement not likely until late in
forecast period.


Iwx watches/warnings/advisories...
Lm...Small Craft Advisory until 7 am EST Saturday for lmz043-046.



short term...Murphy
long term...agd

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