Napoved vremena (od 16.04. do 30.04.2009)

[maestro]

Obdobje lepega in (pre)toplega vremena se za nekaj časa poslavlja. Od zahoda nas je že dosegel rob nove vremenske motnje, ki bo že danes pozno popoldne prinesel prve kaplje na zahod, ponoči in proti jutru pa lahko tudi zagrmi na zahodu, jugozahodu slo. JV,V del SLo pa bo tudi dodobra prepihal jugozahodnik. Tam padavin predvidoma do sobote ne bo skoraj nič oz zelo malo (aladin jih ne namenja nič,medtem ko gfs nekaj malega).

[dominikb]

Že po 27. ali 28 aprilu kaže na poslabšanja. Spremenljivo vreme naj bi bilo tudi pred in po prvomajskih praznikih. Lahko so pa možne še kake spremembe.

[Ciklon]

Čez vikend razmeroma lepo, nato spremenljivo s padavinami.

Sinoptika nad Evropo

Čez vikend bomo prehodno prišli pod vpliv visokega zračnega pritiska nad vzhodno Evropo, med tem pa se bo proti jugu v zahodno Sredozemlje ugrezala dolina hladnega zraka in nizkega zračnega pritiska, ki bo kasneje ob napredovanju proti vzhodu aktivirala nov sekundarni sredozemski ciklon, ki bo s svojo lego in smerjo pomikanja imel bistven vpliv na vreme v Sloveniji.

Napoved

Jutri zjutraj in dopoldne bo precej jasno in sončno. Ponekod po nižinah bo sprva lahko tudi megla. Čez dan bo več oblačnosti, ponekod bodo nastale posamezne krajevne plohe. Najnižje jutranje temperature bodo od 3 do 8, v alpskih dolinah okoli nič in na Primorskem okoli 10, najvišje dnevne od 16 do 21 stopinj Celzija.

V nedeljo bo sprva delno jasno z zmerno oblačnostjo. Popoldne bodo lahko posamezne krajevne plohe. Oblačnost bo od zahoda naraščala. Nekoliko topleje bo kot v soboto. Zvečer bo ob morju zapihal jugo.



Obeti

V ponedeljek bo dopoldne v severovzhodni in deloma v vzhodni Sloveniji še suho vreme. Drugod bo oblačno s padavinami, ki se bodo čez dan nekoliko okrepile in se razširile nad vso državo. Največ dežja bo na zahodu. Jugo ob morju se bo okrepil, drugod po državi pa bo pihal vzhodni do jugovzhodni veter. Hladneje bo.



V torek in sredo se bo nadaljevalo pretežno oblačno vreme z občasnimi padavinami, katerih bo več in bodo pogostejše na zahodu.



Trenutni izgledi za naprej

Proti koncu tedna kaže na še vedno spremenljivo vreme z občasnimi padavinami.
Padavin bo manj, večinoma pa naj bi bile v obliki ploh in neviht.

[dominikb]

Kot je že predhodnik omenil se bo zahodno od nas ustvarila sekundarna depresija v Sredozemlju, ki bo vplivala na vreme pri nas predvsem v zahodnih krajih. To bo najbolj izrazito v ponedeljek , torek in še vse do konca tedna ali pa tja do 1. maja bo še nestalni tip vremena.

[dominikb]

Ker je bil 25. aprila mlaj , ni odveč tudi opozorilo o povišanem plimovanju morja , predvsem s ponedeljka na torek. Pihal bo tudi jugo, v zahodnih krajih pa so možne tudi obilnejše padavine.

[Ciklon]

Kot kažejo nekateri izračuni modelov (GFS, WRF,...) zadnjih nekaj dni, bodo v petek 1. maja popoldne obstajali pogoji za prve resnejše (močnejše) nevihte letos. Verjetnost za te bo večja v vzhodnem delu Slovenije, za naše kraje (Gorenjska) pa bo že sama smer vetrov neugodna za nastanek kaj konkretnejšega.

Rezultati nekaterih izračunov modela GFS in WRF:

...vrednost CAPE bo ponekod tudi okoli 1000 J/kg, index nestabilnosti pa do -5°C:




Temperature rosišča naj bi ble blizu +15°C:


..."zaviranje" konvekcije bo zelo majhna:


...relativna heličnost bo dokaj visoka:


...napredovanje neviht bo proti zahodu-jugozahodu


... Računska GFS sondaža za območje Krškega


Ensembli zadnjih štirih zagonov GFS-ja:





Predvsem vzhodnjaki pripravite fotoaparate, gotovo bo kaj zanimivega za posnet...

[jery_slo]

Kot kaže bodo jutri dobri pogoji za prve resne nevihte. ESTOFEX je že izdal opozorilo:

Storm Forecast
Valid: Thu 30 Apr 2009 06:00 to Fri 01 May 2009 06:00 UTC
Issued: Wed 29 Apr 2009 22:23
Forecaster: GATZEN

SYNOPSIS

A new ridge builds as rising geopotential is forecast from south-western Europe to the Baltic Sea. A low pressure system centred over France and the British Isles will be cut into a northern trough and a southern, merging to long-wave troughs to the north-west of the British Isles and over south-eastern Europe. While rather cool air masses dominate most of western and southern Europe, a tongue of warm air mass is situated from the southern Baltic Sea to the northern Balkans and Ukraine.

DISCUSSION

Northern Balkans

To the north of the trough centred over south-eastern Europe, rather warm air masses are situated over eastern Europe that are expected to spread further south-westward in the wake of the trough. Latest soundings indicate steep lapse rates in the lowest 3 km, while low-level moisture is poor. Best moisture pooling is expected in the range of the warm front over the northern Balkans, where sufficient instability may develop in response to diurnal heating. Cloud coverage will be the greatest forecast uncertainty.

Current thinking is that storms will develop especially over the northern Balkans. The chance of severe convection will gradually increase from the north to the south, as vertical wind shear will be strongest in the range of the warm front, where favourable veering profiles will also be present. Expect a couple of mesocyclones, chance of large hail seems to be high enough to issue a level 1 from northern Bosnia to Hungary and further into western Romania. With isolated storms, a tornado is not completely ruled out as low-level buoyancy and relative humidity may be favourable near the warm front. Severe potential will rapidly decrease in the evening hours as forcing and instability will decrease.

Vir: ESTOFEX

[jery_slo]

Kot kaže se nam jutri obetajo nove nevihte z možnostjo toče. ESTOFEX pravi:

Storm Forecast
Valid: Fri 01 May 2009 06:00 to Sat 02 May 2009 06:00 UTC
Issued: Thu 30 Apr 2009 16:59
Forecaster: TUSCHY

A level 1 was issued for parts of Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Montenegro, Macedonia, parts of central Romania and NE Italy mainly for large hail and isolated severe wind gusts.

A level 1 was issued for parts of Austria and parts of Germany mainly for large hail.

A level 1 was issued for parts of NE Algeria and extreme N-Tunisia mainly for excessive rainfall.


SYNOPSIS

The pattern over Europe features a strong ridge over NW-Europe and an upper low over SE-Europe. In between those systems, cold air at mid-levels advects southwestwards, augmenting the thunderstorm risk over most parts of central Europe. Another outbreak of frigid air over extreme NE-Europe suppresses deep convection for at least the following 24h.

DISCUSSION

... Parts of Slovenia, Croatia, Bosnia and Herzegovina , Serbia, Montenegro, Macedonia, parts of central Romania and NE Italy ...

Latest soundings from Slovakia and Ukraine sample the airmass downstream of those areas well with very steep lapse rates to near 500hPa. GFS sticks to its solution for the past few runs that 2-4km lapse rates of 8-9K/km overspread those regions from the NE already during the morning hours with slightly lower values over Romania. ECMWF and GFS both forecast dewpoints at the surface running from 9-12°C in a concentrated swath just along the Dianaric Alps and those values look reasonable compared to current surface analysis. Strong insolation will push temperatures to well above 20°C, so beside weak capping/the nocturnal inversion, initiation will start during the late morning hours/noon.
Aforementioned environment results in MLCAPE release of 500 - 1500 J/kg. Steep lapse rates, combined with 10-15m/s DLS and some directional shear all point to a large hail risk. This risk is the highest during the early life time when storms are still more discrete. Rising LCLs during the afternoon hours and a dry subcloud layer also augment the risk of severe downbursts.
Betimes, thunderstorms cluster over the mountains and the main hazard then shifts to heavy rain and local flash flooding. Thunderstorms weaken after sunset.

VIR: ESTOFEX

Tudi GFS kaže na kar nekaj CAPE za popoldne:



VIR:Wetterzentrale

[jery_slo]

Danes spet možnost nastanka neviht z veliko točo:

A level 1 was issued for SE Germany, Austria, Slovenia, W Hungary and N Croatia mainly for large hail.

SYNOPSIS

Between a mid/upper-cyclone over the Norwegian Sea and a broad ridge stretching from the central Mediterranean to western Russia, the flow over most of the continent is from the southwest. Another closed low, to the southeast of the ridge, is located over the Sea of Azov and moves to the southeast. A frontal zone is located from western Finland across the Baltic States to central France to NW Spain. A frontal wave develops in the left exit region of a south-westerly speed max over Iberia, and translates to Germany during the afternoon and evening.

SE Germany, Austria, Slovenia, W Hungary and N Croatia...

Shear is forecast to be moderate across most of the area with about 10 m/s of bulk shear forecast in the 0-3 km layer. However, decent amounts of CAPE are forecast, on the order of 1000 J/kg both north and south of the Alps. An attendant threat of large hail is forecast. Model guidance suggests that the storms will be rather isolated and will weaken during the evening.

Tudi tokrat se GFS strinja z ESTOFEX:

[Ciklon]

Vendar, toče večjih dimenzij (> 2 cm) danes ni pričakovati, saj je vetrovni strig prešibek in tudi hitrosti vetra v višinah niso oz. ne bodo visoke.
Glavna dejavnika bosta danes CAPE in T rosišča...

[jkocki]

Vendar, toče večjih dimenzij (> 2 cm) danes ni pričakovati, saj je vetrovni strig prešibek in tudi hitrosti vetra v višinah niso oz. ne bodo visoke.
Glavna dejavnika bosta danes CAPE in T rosišča...

Kako to misliš T rosišča in CAPE?Lahko prosim to malo razložiš, ali že morda kje piše, ker me to zanima, a sem popoln lajk kar se tega tiče.(nevihte, napoved neviht, jakost neviht itd.)

Hvala za odgovor!

Lp

[lukamarti]

khm...

Kako je s tole današnjo napovedjo? Že cel dan nekam oblačno, o padavinah pa ne duha, ne sluha...
Kakšna je možnost da tako ostane tam nekje...jutra? Ali je sploh za pričakovati kakšne obilnejše padavine, nevihte tukaj na gorenjskem?

Lep pozdrav
Luka

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