* Flash flood watch from 10 p.m. tonight through 6 a.m. Thursday *

Radar & lightning: Latest regional radar shows movement of precipitation and lightning strikes over past two hours. Refresh page to update. Click here or on image to enlarge. Or see radar bigger on our Weather Wall.

It was remarkably cool this afternoon, some 20 degrees below average, courtesy of a wedge of cool air penetrating from eastern Canada south into the Carolinas. But as a warm front lifting through the Carolinas displaces the wedge, milder air and waves of tropical moisture surge northward. The end result? Copious amounts of rain over the next 36 hours and an environment increasingly conducive to thunderstorms – which could turn severe late Wednesday.

Through Tonight: On and off rain showers this evening increase in coverage and intensity late at night and towards morning. Heavy rain and thunder is possible, but severe weather is not expected. Temperatures are steady or slowly rise overnight – hovering in the 50-55 degree range. Winds are mostly from the east, around 15 mph, gusting to 20-25 mph at times. Rainfall overnight is probably around 1″, with locally heavier amounts.

Tomorrow (Wednesday): Waves of rain and embedded thunderstorms are likely, and may be heavy. Depending on their exact timing, downpours could easily slow the morning commute. Intermittent stoppages in the rain when the sky brightens are also possible.Flash flooding may occur where heavy rain cells track over the same areas repeatedly or “train.” Day time rainfall totals likely total 1-2 inches, with locally higher amounts.

Late in the afternoon and into the evening, there is a risk of thunderstorms with damaging winds and even some tornadoes, especially south of District – but the entire region should be weather-aware Wednesday.

High temperatures shoot up towards the upper 60s to near 70 late in the day, with winds from the southeast at 15-20 mph, gusting to 25 mph.

See Matt Rogers’ forecast through the weekend. And if you haven’t already, join us on Facebook and follow us on Twitter . For related traffic news, check out Dr. Gridlock.

A rainy walk, April 28. (Ian Livingston via Flickr)

Storm rainfall totals through 5 p.m.: Reagan National 0.64″, Dulles 0.79″, BWI 0.81″

Worth reading – tales of survival and tragedy from tornadoes in South: Tornado Victims Were Dads and Daughters, Brothers and Sons | Incredible Stories of Tornado Survival in Arkansas, Kansas | Arkansas Family Survives Tornado Thanks To Dad’s “Gut” Feeling

Southern storm outbreak, Day 3: Tornado watches – for the third straight day – span parts of the South. The current watches cover western Mississippi and northwest Alabama as well as eastern North Carolina. While a handful of tornado warnings have been issued in eastern North Carolina, so far there have not been reports of destructive tornadoes. But the evening is still young, and dangerous storms remain possible.

Resources to track storms: Latest warnings | Regional Radar – Gulf Coast | Regional Radar – Carolinas

Twitter feeds to follow: @capitalweather @wcl_shawn | @ericholthaus |@wxbrad | @stormchaster4850 | @TWCBreaking | @28storms | @BuzzFeedStorm | @nsj